engine/sqlite/src/expr.cpp
changeset 97 3903521a36da
parent 96 87e863f6f840
child 98 5f9e7e14eb11
--- a/engine/sqlite/src/expr.cpp	Wed May 26 10:44:32 2010 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,2816 +0,0 @@
-/*
-** 2001 September 15
-**
-** The author disclaims copyright to this source code.  In place of
-** a legal notice, here is a blessing:
-**
-**    May you do good and not evil.
-**    May you find forgiveness for yourself and forgive others.
-**    May you share freely, never taking more than you give.
-**
-*************************************************************************
-** This file contains routines used for analyzing expressions and
-** for generating VDBE code that evaluates expressions in SQLite.
-**
-** $Id: expr.cpp 1282 2008-11-13 09:31:33Z LarsPson $
-*/
-#include "sqliteInt.h"
-#include <ctype.h>
-
-/*
-** Return the 'affinity' of the expression pExpr if any.
-**
-** If pExpr is a column, a reference to a column via an 'AS' alias,
-** or a sub-select with a column as the return value, then the 
-** affinity of that column is returned. Otherwise, 0x00 is returned,
-** indicating no affinity for the expression.
-**
-** i.e. the WHERE clause expresssions in the following statements all
-** have an affinity:
-**
-** CREATE TABLE t1(a);
-** SELECT * FROM t1 WHERE a;
-** SELECT a AS b FROM t1 WHERE b;
-** SELECT * FROM t1 WHERE (select a from t1);
-*/
-char sqlite3ExprAffinity(Expr *pExpr){
-  int op = pExpr->op;
-  if( op==TK_SELECT ){
-    return sqlite3ExprAffinity(pExpr->pSelect->pEList->a[0].pExpr);
-  }
-#ifndef SQLITE_OMIT_CAST
-  if( op==TK_CAST ){
-    return sqlite3AffinityType(&pExpr->token);
-  }
-#endif
-  return pExpr->affinity;
-}
-
-/*
-** Set the collating sequence for expression pExpr to be the collating
-** sequence named by pToken.   Return a pointer to the revised expression.
-** The collating sequence is marked as "explicit" using the EP_ExpCollate
-** flag.  An explicit collating sequence will override implicit
-** collating sequences.
-*/
-Expr *sqlite3ExprSetColl(Parse *pParse, Expr *pExpr, Token *pName){
-  char *zColl = 0;            /* Dequoted name of collation sequence */
-  CollSeq *pColl;
-  zColl = sqlite3NameFromToken(pParse->db, pName);
-  if( pExpr && zColl ){
-    pColl = sqlite3LocateCollSeq(pParse, zColl, -1);
-    if( pColl ){
-      pExpr->pColl = pColl;
-      pExpr->flags |= EP_ExpCollate;
-    }
-  }
-  sqlite3_free(zColl);
-  return pExpr;
-}
-
-/*
-** Return the default collation sequence for the expression pExpr. If
-** there is no default collation type, return 0.
-*/
-CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr){
-  CollSeq *pColl = 0;
-  if( pExpr ){
-    int op;
-    pColl = pExpr->pColl;
-    op = pExpr->op;
-    if( (op==TK_CAST || op==TK_UPLUS) && !pColl ){
-      return sqlite3ExprCollSeq(pParse, pExpr->pLeft);
-    }
-  }
-  if( sqlite3CheckCollSeq(pParse, pColl) ){ 
-    pColl = 0;
-  }
-  return pColl;
-}
-
-/*
-** pExpr is an operand of a comparison operator.  aff2 is the
-** type affinity of the other operand.  This routine returns the
-** type affinity that should be used for the comparison operator.
-*/
-char sqlite3CompareAffinity(Expr *pExpr, char aff2){
-  char aff1 = sqlite3ExprAffinity(pExpr);
-  if( aff1 && aff2 ){
-    /* Both sides of the comparison are columns. If one has numeric
-    ** affinity, use that. Otherwise use no affinity.
-    */
-    if( sqlite3IsNumericAffinity(aff1) || sqlite3IsNumericAffinity(aff2) ){
-      return SQLITE_AFF_NUMERIC;
-    }else{
-      return SQLITE_AFF_NONE;
-    }
-  }else if( !aff1 && !aff2 ){
-    /* Neither side of the comparison is a column.  Compare the
-    ** results directly.
-    */
-    return SQLITE_AFF_NONE;
-  }else{
-    /* One side is a column, the other is not. Use the columns affinity. */
-    assert( aff1==0 || aff2==0 );
-    return (aff1 + aff2);
-  }
-}
-
-/*
-** pExpr is a comparison operator.  Return the type affinity that should
-** be applied to both operands prior to doing the comparison.
-*/
-static char comparisonAffinity(Expr *pExpr){
-  char aff;
-  assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
-          pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
-          pExpr->op==TK_NE );
-  assert( pExpr->pLeft );
-  aff = sqlite3ExprAffinity(pExpr->pLeft);
-  if( pExpr->pRight ){
-    aff = sqlite3CompareAffinity(pExpr->pRight, aff);
-  }
-  else if( pExpr->pSelect ){
-    aff = sqlite3CompareAffinity(pExpr->pSelect->pEList->a[0].pExpr, aff);
-  }
-  else if( !aff ){
-    aff = SQLITE_AFF_NONE;
-  }
-  return aff;
-}
-
-/*
-** pExpr is a comparison expression, eg. '=', '<', IN(...) etc.
-** idx_affinity is the affinity of an indexed column. Return true
-** if the index with affinity idx_affinity may be used to implement
-** the comparison in pExpr.
-*/
-int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity){
-  char aff = comparisonAffinity(pExpr);
-  switch( aff ){
-    case SQLITE_AFF_NONE:
-      return 1;
-    case SQLITE_AFF_TEXT:
-      return idx_affinity==SQLITE_AFF_TEXT;
-    default:
-      return sqlite3IsNumericAffinity(idx_affinity);
-  }
-}
-
-/*
-** Return the P1 value that should be used for a binary comparison
-** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2.
-** If jumpIfNull is true, then set the low byte of the returned
-** P1 value to tell the opcode to jump if either expression
-** evaluates to NULL.
-*/
-static int binaryCompareP1(Expr *pExpr1, Expr *pExpr2, int jumpIfNull){
-  char aff = sqlite3ExprAffinity(pExpr2);
-  return ((int)sqlite3CompareAffinity(pExpr1, aff))+(jumpIfNull?0x100:0);
-}
-
-/*
-** Return a pointer to the collation sequence that should be used by
-** a binary comparison operator comparing pLeft and pRight.
-**
-** If the left hand expression has a collating sequence type, then it is
-** used. Otherwise the collation sequence for the right hand expression
-** is used, or the default (BINARY) if neither expression has a collating
-** type.
-**
-** Argument pRight (but not pLeft) may be a null pointer. In this case,
-** it is not considered.
-*/
-CollSeq *sqlite3BinaryCompareCollSeq(
-  Parse *pParse, 
-  Expr *pLeft, 
-  Expr *pRight
-){
-  CollSeq *pColl;
-  assert( pLeft );
-  if( pLeft->flags & EP_ExpCollate ){
-    assert( pLeft->pColl );
-    pColl = pLeft->pColl;
-  }else if( pRight && pRight->flags & EP_ExpCollate ){
-    assert( pRight->pColl );
-    pColl = pRight->pColl;
-  }else{
-    pColl = sqlite3ExprCollSeq(pParse, pLeft);
-    if( !pColl ){
-      pColl = sqlite3ExprCollSeq(pParse, pRight);
-    }
-  }
-  return pColl;
-}
-
-/*
-** Generate code for a comparison operator.
-*/
-static int codeCompare(
-  Parse *pParse,    /* The parsing (and code generating) context */
-  Expr *pLeft,      /* The left operand */
-  Expr *pRight,     /* The right operand */
-  int opcode,       /* The comparison opcode */
-  int dest,         /* Jump here if true.  */
-  int jumpIfNull    /* If true, jump if either operand is NULL */
-){
-  int p1 = binaryCompareP1(pLeft, pRight, jumpIfNull);
-  CollSeq *p3 = sqlite3BinaryCompareCollSeq(pParse, pLeft, pRight);
-  return sqlite3VdbeOp3(pParse->pVdbe, opcode, p1, dest, (const char*)p3, P3_COLLSEQ);
-}
-
-/*
-** Construct a new expression node and return a pointer to it.  Memory
-** for this node is obtained from sqlite3_malloc().  The calling function
-** is responsible for making sure the node eventually gets freed.
-*/
-Expr *sqlite3Expr(
-  sqlite3 *db,            /* Handle for sqlite3DbMallocZero() (may be null) */
-  int op,                 /* Expression opcode */
-  Expr *pLeft,            /* Left operand */
-  Expr *pRight,           /* Right operand */
-  const Token *pToken     /* Argument token */
-){
-  Expr *pNew;
-  pNew = (Expr*)sqlite3DbMallocZero(db, sizeof(Expr));
-  if( pNew==0 ){
-    /* When malloc fails, delete pLeft and pRight. Expressions passed to 
-    ** this function must always be allocated with sqlite3Expr() for this 
-    ** reason. 
-    */
-    sqlite3ExprDelete(pLeft);
-    sqlite3ExprDelete(pRight);
-    return 0;
-  }
-  pNew->op = op;
-  pNew->pLeft = pLeft;
-  pNew->pRight = pRight;
-  pNew->iAgg = -1;
-  if( pToken ){
-    assert( pToken->dyn==0 );
-    pNew->span = pNew->token = *pToken;
-  }else if( pLeft ){
-    if( pRight ){
-      sqlite3ExprSpan(pNew, &pLeft->span, &pRight->span);
-      if( pRight->flags & EP_ExpCollate ){
-        pNew->flags |= EP_ExpCollate;
-        pNew->pColl = pRight->pColl;
-      }
-    }
-    if( pLeft->flags & EP_ExpCollate ){
-      pNew->flags |= EP_ExpCollate;
-      pNew->pColl = pLeft->pColl;
-    }
-  }
-
-  sqlite3ExprSetHeight(pNew);
-  return pNew;
-}
-
-/*
-** Works like sqlite3Expr() except that it takes an extra Parse*
-** argument and notifies the associated connection object if malloc fails.
-*/
-Expr *sqlite3PExpr(
-  Parse *pParse,          /* Parsing context */
-  int op,                 /* Expression opcode */
-  Expr *pLeft,            /* Left operand */
-  Expr *pRight,           /* Right operand */
-  const Token *pToken     /* Argument token */
-){
-  return sqlite3Expr(pParse->db, op, pLeft, pRight, pToken);
-}
-
-/*
-** When doing a nested parse, you can include terms in an expression
-** that look like this:   #0 #1 #2 ...  These terms refer to elements
-** on the stack.  "#0" means the top of the stack.
-** "#1" means the next down on the stack.  And so forth.
-**
-** This routine is called by the parser to deal with on of those terms.
-** It immediately generates code to store the value in a memory location.
-** The returns an expression that will code to extract the value from
-** that memory location as needed.
-*/
-Expr *sqlite3RegisterExpr(Parse *pParse, Token *pToken){
-  Vdbe *v = pParse->pVdbe;
-  Expr *p;
-  int depth;
-  if( pParse->nested==0 ){
-    sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", pToken);
-    return sqlite3PExpr(pParse, TK_NULL, 0, 0, 0);
-  }
-  if( v==0 ) return 0;
-  p = sqlite3PExpr(pParse, TK_REGISTER, 0, 0, pToken);
-  if( p==0 ){
-    return 0;  /* Malloc failed */
-  }
-  depth = atoi((char*)&pToken->z[1]);
-  p->iTable = pParse->nMem++;
-  sqlite3VdbeAddOp(v, OP_Dup, depth, 0);
-  sqlite3VdbeAddOp(v, OP_MemStore, p->iTable, 1);
-  return p;
-}
-
-/*
-** Join two expressions using an AND operator.  If either expression is
-** NULL, then just return the other expression.
-*/
-Expr *sqlite3ExprAnd(sqlite3 *db, Expr *pLeft, Expr *pRight){
-  if( pLeft==0 ){
-    return pRight;
-  }else if( pRight==0 ){
-    return pLeft;
-  }else{
-    return sqlite3Expr(db, TK_AND, pLeft, pRight, 0);
-  }
-}
-
-/*
-** Set the Expr.span field of the given expression to span all
-** text between the two given tokens.
-*/
-void sqlite3ExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
-  assert( pRight!=0 );
-  assert( pLeft!=0 );
-  if( pExpr && pRight->z && pLeft->z ){
-    assert( pLeft->dyn==0 || pLeft->z[pLeft->n]==0 );
-    if( pLeft->dyn==0 && pRight->dyn==0 ){
-      pExpr->span.z = pLeft->z;
-      pExpr->span.n = pRight->n + (pRight->z - pLeft->z);
-    }else{
-      pExpr->span.z = 0;
-    }
-  }
-}
-
-/*
-** Construct a new expression node for a function with multiple
-** arguments.
-*/
-Expr *sqlite3ExprFunction(Parse *pParse, ExprList *pList, Token *pToken){
-  Expr *pNew;
-  assert( pToken );
-  pNew = (Expr*)sqlite3DbMallocZero(pParse->db, sizeof(Expr) );
-  if( pNew==0 ){
-    sqlite3ExprListDelete(pList); /* Avoid leaking memory when malloc fails */
-    return 0;
-  }
-  pNew->op = TK_FUNCTION;
-  pNew->pList = pList;
-  assert( pToken->dyn==0 );
-  pNew->token = *pToken;
-  pNew->span = pNew->token;
-
-  sqlite3ExprSetHeight(pNew);
-  return pNew;
-}
-
-/*
-** Assign a variable number to an expression that encodes a wildcard
-** in the original SQL statement.  
-**
-** Wildcards consisting of a single "?" are assigned the next sequential
-** variable number.
-**
-** Wildcards of the form "?nnn" are assigned the number "nnn".  We make
-** sure "nnn" is not too be to avoid a denial of service attack when
-** the SQL statement comes from an external source.
-**
-** Wildcards of the form ":aaa" or "$aaa" are assigned the same number
-** as the previous instance of the same wildcard.  Or if this is the first
-** instance of the wildcard, the next sequenial variable number is
-** assigned.
-*/
-void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
-  Token *pToken;
-  sqlite3 *db = pParse->db;
-
-  if( pExpr==0 ) return;
-  pToken = &pExpr->token;
-  assert( pToken->n>=1 );
-  assert( pToken->z!=0 );
-  assert( pToken->z[0]!=0 );
-  if( pToken->n==1 ){
-    /* Wildcard of the form "?".  Assign the next variable number */
-    pExpr->iTable = ++pParse->nVar;
-  }else if( pToken->z[0]=='?' ){
-    /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
-    ** use it as the variable number */
-    int i;
-    pExpr->iTable = i = atoi((char*)&pToken->z[1]);
-    if( i<1 || i>SQLITE_MAX_VARIABLE_NUMBER ){
-      sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
-          SQLITE_MAX_VARIABLE_NUMBER);
-    }
-    if( i>pParse->nVar ){
-      pParse->nVar = i;
-    }
-  }else{
-    /* Wildcards of the form ":aaa" or "$aaa".  Reuse the same variable
-    ** number as the prior appearance of the same name, or if the name
-    ** has never appeared before, reuse the same variable number
-    */
-    int i, n;
-    n = pToken->n;
-    for(i=0; i<pParse->nVarExpr; i++){
-      Expr *pE;
-      if( (pE = pParse->apVarExpr[i])!=0
-          && pE->token.n==n
-          && memcmp(pE->token.z, pToken->z, n)==0 ){
-        pExpr->iTable = pE->iTable;
-        break;
-      }
-    }
-    if( i>=pParse->nVarExpr ){
-      pExpr->iTable = ++pParse->nVar;
-      if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
-        pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
-        pParse->apVarExpr =
-            (Expr**)sqlite3DbReallocOrFree(
-              db,
-              pParse->apVarExpr,
-              pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0])
-            );
-      }
-      if( !db->mallocFailed ){
-        assert( pParse->apVarExpr!=0 );
-        pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
-      }
-    }
-  } 
-  if( !pParse->nErr && pParse->nVar>SQLITE_MAX_VARIABLE_NUMBER ){
-    sqlite3ErrorMsg(pParse, "too many SQL variables");
-  }
-}
-
-/*
-** Recursively delete an expression tree.
-*/
-void sqlite3ExprDelete(Expr *p){
-  if( p==0 ) return;
-  if( p->span.dyn ) sqlite3_free((char*)p->span.z);
-  if( p->token.dyn ) sqlite3_free((char*)p->token.z);
-  sqlite3ExprDelete(p->pLeft);
-  sqlite3ExprDelete(p->pRight);
-  sqlite3ExprListDelete(p->pList);
-  sqlite3SelectDelete(p->pSelect);
-  sqlite3_free(p);
-}
-
-/*
-** The Expr.token field might be a string literal that is quoted.
-** If so, remove the quotation marks.
-*/
-void sqlite3DequoteExpr(sqlite3 *db, Expr *p){
-  if( ExprHasAnyProperty(p, EP_Dequoted) ){
-    return;
-  }
-  ExprSetProperty(p, EP_Dequoted);
-  if( p->token.dyn==0 ){
-    sqlite3TokenCopy(db, &p->token, &p->token);
-  }
-  sqlite3Dequote((char*)p->token.z);
-}
-
-
-/*
-** The following group of routines make deep copies of expressions,
-** expression lists, ID lists, and select statements.  The copies can
-** be deleted (by being passed to their respective ...Delete() routines)
-** without effecting the originals.
-**
-** The expression list, ID, and source lists return by sqlite3ExprListDup(),
-** sqlite3IdListDup(), and sqlite3SrcListDup() can not be further expanded 
-** by subsequent calls to sqlite*ListAppend() routines.
-**
-** Any tables that the SrcList might point to are not duplicated.
-*/
-Expr *sqlite3ExprDup(sqlite3 *db, Expr *p){
-  Expr *pNew;
-  if( p==0 ) return 0;
-  pNew = (Expr*)sqlite3DbMallocRaw(db, sizeof(*p) );
-  if( pNew==0 ) return 0;
-  memcpy(pNew, p, sizeof(*pNew));
-  if( p->token.z!=0 ){
-    pNew->token.z = (u8*)sqlite3DbStrNDup(db, (char*)p->token.z, p->token.n);
-    pNew->token.dyn = 1;
-  }else{
-    assert( pNew->token.z==0 );
-  }
-  pNew->span.z = 0;
-  pNew->pLeft = sqlite3ExprDup(db, p->pLeft);
-  pNew->pRight = sqlite3ExprDup(db, p->pRight);
-  pNew->pList = sqlite3ExprListDup(db, p->pList);
-  pNew->pSelect = sqlite3SelectDup(db, p->pSelect);
-  return pNew;
-}
-void sqlite3TokenCopy(sqlite3 *db, Token *pTo, Token *pFrom){
-  if( pTo->dyn ) sqlite3_free((char*)pTo->z);
-  if( pFrom->z ){
-    pTo->n = pFrom->n;
-    pTo->z = (u8*)sqlite3DbStrNDup(db, (char*)pFrom->z, pFrom->n);
-    pTo->dyn = 1;
-  }else{
-    pTo->z = 0;
-  }
-}
-ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p){
-  ExprList *pNew;
-  ExprList::ExprList_item *pItem, *pOldItem;
-  int i;
-  if( p==0 ) return 0;
-  pNew = (ExprList*)sqlite3DbMallocRaw(db, sizeof(*pNew) );
-  if( pNew==0 ) return 0;
-  pNew->iECursor = 0;
-  pNew->nExpr = pNew->nAlloc = p->nExpr;
-  pNew->a = pItem = (ExprList::ExprList_item*)sqlite3DbMallocRaw(db,  p->nExpr*sizeof(p->a[0]) );
-  if( pItem==0 ){
-    sqlite3_free(pNew);
-    return 0;
-  } 
-  pOldItem = p->a;
-  for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){
-    Expr *pNewExpr, *pOldExpr;
-    pItem->pExpr = pNewExpr = sqlite3ExprDup(db, pOldExpr = pOldItem->pExpr);
-    if( pOldExpr->span.z!=0 && pNewExpr ){
-      /* Always make a copy of the span for top-level expressions in the
-      ** expression list.  The logic in SELECT processing that determines
-      ** the names of columns in the result set needs this information */
-      sqlite3TokenCopy(db, &pNewExpr->span, &pOldExpr->span);
-    }
-    assert( pNewExpr==0 || pNewExpr->span.z!=0 
-            || pOldExpr->span.z==0
-            || db->mallocFailed );
-    pItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
-    pItem->sortOrder = pOldItem->sortOrder;
-    pItem->isAgg = pOldItem->isAgg;
-    pItem->done = 0;
-  }
-  return pNew;
-}
-
-/*
-** If cursors, triggers, views and subqueries are all omitted from
-** the build, then none of the following routines, except for 
-** sqlite3SelectDup(), can be called. sqlite3SelectDup() is sometimes
-** called with a NULL argument.
-*/
-#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \
- || !defined(SQLITE_OMIT_SUBQUERY)
-SrcList *sqlite3SrcListDup(sqlite3 *db, SrcList *p){
-  SrcList *pNew;
-  int i;
-  int nByte;
-  if( p==0 ) return 0;
-  nByte = sizeof(*p) + (p->nSrc>0 ? sizeof(p->a[0]) * (p->nSrc-1) : 0);
-  pNew = (SrcList*)sqlite3DbMallocRaw(db, nByte );
-  if( pNew==0 ) return 0;
-  pNew->nSrc = pNew->nAlloc = p->nSrc;
-  for(i=0; i<p->nSrc; i++){
-	  SrcList::SrcList_item *pNewItem = &pNew->a[i];
-	  SrcList::SrcList_item *pOldItem = &p->a[i];
-    Table *pTab;
-    pNewItem->zDatabase = sqlite3DbStrDup(db, pOldItem->zDatabase);
-    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
-    pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
-    pNewItem->jointype = pOldItem->jointype;
-    pNewItem->iCursor = pOldItem->iCursor;
-    pNewItem->isPopulated = pOldItem->isPopulated;
-    pTab = pNewItem->pTab = pOldItem->pTab;
-    if( pTab ){
-      pTab->nRef++;
-    }
-    pNewItem->pSelect = sqlite3SelectDup(db, pOldItem->pSelect);
-    pNewItem->pOn = sqlite3ExprDup(db, pOldItem->pOn);
-    pNewItem->pUsing = sqlite3IdListDup(db, pOldItem->pUsing);
-    pNewItem->colUsed = pOldItem->colUsed;
-  }
-  return pNew;
-}
-IdList *sqlite3IdListDup(sqlite3 *db, IdList *p){
-  IdList *pNew;
-  int i;
-  if( p==0 ) return 0;
-  pNew = (IdList*)sqlite3DbMallocRaw(db, sizeof(*pNew) );
-  if( pNew==0 ) return 0;
-  pNew->nId = pNew->nAlloc = p->nId;
-  pNew->a = (IdList::IdList_item*)sqlite3DbMallocRaw(db, p->nId*sizeof(p->a[0]) );
-  if( pNew->a==0 ){
-    sqlite3_free(pNew);
-    return 0;
-  }
-  for(i=0; i<p->nId; i++){
-	  IdList::IdList_item *pNewItem = &pNew->a[i];
-	  IdList::IdList_item *pOldItem = &p->a[i];
-    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
-    pNewItem->idx = pOldItem->idx;
-  }
-  return pNew;
-}
-Select *sqlite3SelectDup(sqlite3 *db, Select *p){
-  Select *pNew;
-  if( p==0 ) return 0;
-  pNew = (Select*)sqlite3DbMallocRaw(db, sizeof(*p) );
-  if( pNew==0 ) return 0;
-  pNew->isDistinct = p->isDistinct;
-  pNew->pEList = sqlite3ExprListDup(db, p->pEList);
-  pNew->pSrc = sqlite3SrcListDup(db, p->pSrc);
-  pNew->pWhere = sqlite3ExprDup(db, p->pWhere);
-  pNew->pGroupBy = sqlite3ExprListDup(db, p->pGroupBy);
-  pNew->pHaving = sqlite3ExprDup(db, p->pHaving);
-  pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy);
-  pNew->op = p->op;
-  pNew->pPrior = sqlite3SelectDup(db, p->pPrior);
-  pNew->pLimit = sqlite3ExprDup(db, p->pLimit);
-  pNew->pOffset = sqlite3ExprDup(db, p->pOffset);
-  pNew->iLimit = -1;
-  pNew->iOffset = -1;
-  pNew->isResolved = p->isResolved;
-  pNew->isAgg = p->isAgg;
-  pNew->usesEphm = 0;
-  pNew->disallowOrderBy = 0;
-  pNew->pRightmost = 0;
-  pNew->addrOpenEphm[0] = -1;
-  pNew->addrOpenEphm[1] = -1;
-  pNew->addrOpenEphm[2] = -1;
-  return pNew;
-}
-#else
-Select *sqlite3SelectDup(sqlite3 *db, Select *p){
-  assert( p==0 );
-  return 0;
-}
-#endif
-
-
-/*
-** Add a new element to the end of an expression list.  If pList is
-** initially NULL, then create a new expression list.
-*/
-ExprList *sqlite3ExprListAppend(
-  Parse *pParse,          /* Parsing context */
-  ExprList *pList,        /* List to which to append. Might be NULL */
-  Expr *pExpr,            /* Expression to be appended */
-  Token *pName            /* AS keyword for the expression */
-){
-  sqlite3 *db = pParse->db;
-  if( pList==0 ){
-    pList = (ExprList*)sqlite3DbMallocZero(db, sizeof(ExprList) );
-    if( pList==0 ){
-      goto no_mem;
-    }
-    assert( pList->nAlloc==0 );
-  }
-  if( pList->nAlloc<=pList->nExpr ){
-	  ExprList::ExprList_item *a;
-    int n = pList->nAlloc*2 + 4;
-	a = (ExprList::ExprList_item*)sqlite3DbRealloc(db, pList->a, n*sizeof(pList->a[0]));
-    if( a==0 ){
-      goto no_mem;
-    }
-    pList->a = a;
-    pList->nAlloc = n;
-  }
-  assert( pList->a!=0 );
-  if( pExpr || pName ){
-	  ExprList::ExprList_item *pItem = &pList->a[pList->nExpr++];
-    memset(pItem, 0, sizeof(*pItem));
-    pItem->zName = sqlite3NameFromToken(db, pName);
-    pItem->pExpr = pExpr;
-  }
-  return pList;
-
-no_mem:     
-  /* Avoid leaking memory if malloc has failed. */
-  sqlite3ExprDelete(pExpr);
-  sqlite3ExprListDelete(pList);
-  return 0;
-}
-
-/*
-** If the expression list pEList contains more than iLimit elements,
-** leave an error message in pParse.
-*/
-void sqlite3ExprListCheckLength(
-  Parse *pParse,
-  ExprList *pEList,
-  int iLimit,
-  const char *zObject
-){
-  if( pEList && pEList->nExpr>iLimit ){
-    sqlite3ErrorMsg(pParse, "too many columns in %s", zObject);
-  }
-}
-
-
-#if defined(SQLITE_TEST) || SQLITE_MAX_EXPR_DEPTH>0
-/* The following three functions, heightOfExpr(), heightOfExprList()
-** and heightOfSelect(), are used to determine the maximum height
-** of any expression tree referenced by the structure passed as the
-** first argument.
-**
-** If this maximum height is greater than the current value pointed
-** to by pnHeight, the second parameter, then set *pnHeight to that
-** value.
-*/
-static void heightOfExpr(Expr *p, int *pnHeight){
-  if( p ){
-    if( p->nHeight>*pnHeight ){
-      *pnHeight = p->nHeight;
-    }
-  }
-}
-static void heightOfExprList(ExprList *p, int *pnHeight){
-  if( p ){
-    int i;
-    for(i=0; i<p->nExpr; i++){
-      heightOfExpr(p->a[i].pExpr, pnHeight);
-    }
-  }
-}
-static void heightOfSelect(Select *p, int *pnHeight){
-  if( p ){
-    heightOfExpr(p->pWhere, pnHeight);
-    heightOfExpr(p->pHaving, pnHeight);
-    heightOfExpr(p->pLimit, pnHeight);
-    heightOfExpr(p->pOffset, pnHeight);
-    heightOfExprList(p->pEList, pnHeight);
-    heightOfExprList(p->pGroupBy, pnHeight);
-    heightOfExprList(p->pOrderBy, pnHeight);
-    heightOfSelect(p->pPrior, pnHeight);
-  }
-}
-
-/*
-** Set the Expr.nHeight variable in the structure passed as an 
-** argument. An expression with no children, Expr.pList or 
-** Expr.pSelect member has a height of 1. Any other expression
-** has a height equal to the maximum height of any other 
-** referenced Expr plus one.
-*/
-void sqlite3ExprSetHeight(Expr *p){
-  int nHeight = 0;
-  heightOfExpr(p->pLeft, &nHeight);
-  heightOfExpr(p->pRight, &nHeight);
-  heightOfExprList(p->pList, &nHeight);
-  heightOfSelect(p->pSelect, &nHeight);
-  p->nHeight = nHeight + 1;
-}
-
-/*
-** Return the maximum height of any expression tree referenced
-** by the select statement passed as an argument.
-*/
-int sqlite3SelectExprHeight(Select *p){
-  int nHeight = 0;
-  heightOfSelect(p, &nHeight);
-  return nHeight;
-}
-#endif
-
-/*
-** Delete an entire expression list.
-*/
-void sqlite3ExprListDelete(ExprList *pList){
-  int i;
-  ExprList::ExprList_item *pItem;
-  if( pList==0 ) return;
-  assert( pList->a!=0 || (pList->nExpr==0 && pList->nAlloc==0) );
-  assert( pList->nExpr<=pList->nAlloc );
-  for(pItem=pList->a, i=0; i<pList->nExpr; i++, pItem++){
-    sqlite3ExprDelete(pItem->pExpr);
-    sqlite3_free(pItem->zName);
-  }
-  sqlite3_free(pList->a);
-  sqlite3_free(pList);
-}
-
-/*
-** Walk an expression tree.  Call xFunc for each node visited.
-**
-** The return value from xFunc determines whether the tree walk continues.
-** 0 means continue walking the tree.  1 means do not walk children
-** of the current node but continue with siblings.  2 means abandon
-** the tree walk completely.
-**
-** The return value from this routine is 1 to abandon the tree walk
-** and 0 to continue.
-**
-** NOTICE:  This routine does *not* descend into subqueries.
-*/
-static int walkExprList(ExprList *, int (*)(void *, Expr*), void *);
-static int walkExprTree(Expr *pExpr, int (*xFunc)(void*,Expr*), void *pArg){
-  int rc;
-  if( pExpr==0 ) return 0;
-  rc = (*xFunc)(pArg, pExpr);
-  if( rc==0 ){
-    if( walkExprTree(pExpr->pLeft, xFunc, pArg) ) return 1;
-    if( walkExprTree(pExpr->pRight, xFunc, pArg) ) return 1;
-    if( walkExprList(pExpr->pList, xFunc, pArg) ) return 1;
-  }
-  return rc>1;
-}
-
-/*
-** Call walkExprTree() for every expression in list p.
-*/
-static int walkExprList(ExprList *p, int (*xFunc)(void *, Expr*), void *pArg){
-  int i;
-  ExprList::ExprList_item *pItem;
-  if( !p ) return 0;
-  for(i=p->nExpr, pItem=p->a; i>0; i--, pItem++){
-    if( walkExprTree(pItem->pExpr, xFunc, pArg) ) return 1;
-  }
-  return 0;
-}
-
-/*
-** Call walkExprTree() for every expression in Select p, not including
-** expressions that are part of sub-selects in any FROM clause or the LIMIT
-** or OFFSET expressions..
-*/
-static int walkSelectExpr(Select *p, int (*xFunc)(void *, Expr*), void *pArg){
-  walkExprList(p->pEList, xFunc, pArg);
-  walkExprTree(p->pWhere, xFunc, pArg);
-  walkExprList(p->pGroupBy, xFunc, pArg);
-  walkExprTree(p->pHaving, xFunc, pArg);
-  walkExprList(p->pOrderBy, xFunc, pArg);
-  if( p->pPrior ){
-    walkSelectExpr(p->pPrior, xFunc, pArg);
-  }
-  return 0;
-}
-
-
-/*
-** This routine is designed as an xFunc for walkExprTree().
-**
-** pArg is really a pointer to an integer.  If we can tell by looking
-** at pExpr that the expression that contains pExpr is not a constant
-** expression, then set *pArg to 0 and return 2 to abandon the tree walk.
-** If pExpr does does not disqualify the expression from being a constant
-** then do nothing.
-**
-** After walking the whole tree, if no nodes are found that disqualify
-** the expression as constant, then we assume the whole expression
-** is constant.  See sqlite3ExprIsConstant() for additional information.
-*/
-static int exprNodeIsConstant(void *pArg, Expr *pExpr){
-  int *pN = (int*)pArg;
-
-  /* If *pArg is 3 then any term of the expression that comes from
-  ** the ON or USING clauses of a join disqualifies the expression
-  ** from being considered constant. */
-  if( (*pN)==3 && ExprHasAnyProperty(pExpr, EP_FromJoin) ){
-    *pN = 0;
-    return 2;
-  }
-
-  switch( pExpr->op ){
-    /* Consider functions to be constant if all their arguments are constant
-    ** and *pArg==2 */
-    case TK_FUNCTION:
-      if( (*pN)==2 ) return 0;
-      /* Fall through */
-    case TK_ID:
-    case TK_COLUMN:
-    case TK_DOT:
-    case TK_AGG_FUNCTION:
-    case TK_AGG_COLUMN:
-#ifndef SQLITE_OMIT_SUBQUERY
-    case TK_SELECT:
-    case TK_EXISTS:
-#endif
-      *pN = 0;
-      return 2;
-    case TK_IN:
-      if( pExpr->pSelect ){
-        *pN = 0;
-        return 2;
-      }
-    default:
-      return 0;
-  }
-}
-
-/*
-** Walk an expression tree.  Return 1 if the expression is constant
-** and 0 if it involves variables or function calls.
-**
-** For the purposes of this function, a double-quoted string (ex: "abc")
-** is considered a variable but a single-quoted string (ex: 'abc') is
-** a constant.
-*/
-int sqlite3ExprIsConstant(Expr *p){
-  int isConst = 1;
-  walkExprTree(p, exprNodeIsConstant, &isConst);
-  return isConst;
-}
-
-/*
-** Walk an expression tree.  Return 1 if the expression is constant
-** that does no originate from the ON or USING clauses of a join.
-** Return 0 if it involves variables or function calls or terms from
-** an ON or USING clause.
-*/
-int sqlite3ExprIsConstantNotJoin(Expr *p){
-  int isConst = 3;
-  walkExprTree(p, exprNodeIsConstant, &isConst);
-  return isConst!=0;
-}
-
-/*
-** Walk an expression tree.  Return 1 if the expression is constant
-** or a function call with constant arguments.  Return and 0 if there
-** are any variables.
-**
-** For the purposes of this function, a double-quoted string (ex: "abc")
-** is considered a variable but a single-quoted string (ex: 'abc') is
-** a constant.
-*/
-int sqlite3ExprIsConstantOrFunction(Expr *p){
-  int isConst = 2;
-  walkExprTree(p, exprNodeIsConstant, &isConst);
-  return isConst!=0;
-}
-
-/*
-** If the expression p codes a constant integer that is small enough
-** to fit in a 32-bit integer, return 1 and put the value of the integer
-** in *pValue.  If the expression is not an integer or if it is too big
-** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
-*/
-int sqlite3ExprIsInteger(Expr *p, int *pValue){
-  switch( p->op ){
-    case TK_INTEGER: {
-      if( sqlite3GetInt32((char*)p->token.z, pValue) ){
-        return 1;
-      }
-      break;
-    }
-    case TK_UPLUS: {
-      return sqlite3ExprIsInteger(p->pLeft, pValue);
-    }
-    case TK_UMINUS: {
-      int v;
-      if( sqlite3ExprIsInteger(p->pLeft, &v) ){
-        *pValue = -v;
-        return 1;
-      }
-      break;
-    }
-    default: break;
-  }
-  return 0;
-}
-
-/*
-** Return TRUE if the given string is a row-id column name.
-*/
-int sqlite3IsRowid(const char *z){
-  if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1;
-  if( sqlite3StrICmp(z, "ROWID")==0 ) return 1;
-  if( sqlite3StrICmp(z, "OID")==0 ) return 1;
-  return 0;
-}
-
-/*
-** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
-** that name in the set of source tables in pSrcList and make the pExpr 
-** expression node refer back to that source column.  The following changes
-** are made to pExpr:
-**
-**    pExpr->iDb           Set the index in db->aDb[] of the database holding
-**                         the table.
-**    pExpr->iTable        Set to the cursor number for the table obtained
-**                         from pSrcList.
-**    pExpr->iColumn       Set to the column number within the table.
-**    pExpr->op            Set to TK_COLUMN.
-**    pExpr->pLeft         Any expression this points to is deleted
-**    pExpr->pRight        Any expression this points to is deleted.
-**
-** The pDbToken is the name of the database (the "X").  This value may be
-** NULL meaning that name is of the form Y.Z or Z.  Any available database
-** can be used.  The pTableToken is the name of the table (the "Y").  This
-** value can be NULL if pDbToken is also NULL.  If pTableToken is NULL it
-** means that the form of the name is Z and that columns from any table
-** can be used.
-**
-** If the name cannot be resolved unambiguously, leave an error message
-** in pParse and return non-zero.  Return zero on success.
-*/
-static int lookupName(
-  Parse *pParse,       /* The parsing context */
-  Token *pDbToken,     /* Name of the database containing table, or NULL */
-  Token *pTableToken,  /* Name of table containing column, or NULL */
-  Token *pColumnToken, /* Name of the column. */
-  NameContext *pNC,    /* The name context used to resolve the name */
-  Expr *pExpr          /* Make this EXPR node point to the selected column */
-){
-  char *zDb = 0;       /* Name of the database.  The "X" in X.Y.Z */
-  char *zTab = 0;      /* Name of the table.  The "Y" in X.Y.Z or Y.Z */
-  char *zCol = 0;      /* Name of the column.  The "Z" */
-  int i, j;            /* Loop counters */
-  int cnt = 0;         /* Number of matching column names */
-  int cntTab = 0;      /* Number of matching table names */
-  sqlite3 *db = pParse->db;  /* The database */
-  SrcList::SrcList_item *pItem;       /* Use for looping over pSrcList items */
-  SrcList::SrcList_item *pMatch = 0;  /* The matching pSrcList item */
-  NameContext *pTopNC = pNC;        /* First namecontext in the list */
-  Schema *pSchema = 0;              /* Schema of the expression */
-
-  assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
-  zDb = sqlite3NameFromToken(db, pDbToken);
-  zTab = sqlite3NameFromToken(db, pTableToken);
-  zCol = sqlite3NameFromToken(db, pColumnToken);
-  if( db->mallocFailed ){
-    goto lookupname_end;
-  }
-
-  pExpr->iTable = -1;
-  while( pNC && cnt==0 ){
-    ExprList *pEList;
-    SrcList *pSrcList = pNC->pSrcList;
-
-    if( pSrcList ){
-      for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
-        Table *pTab;
-        int iDb;
-        Column *pCol;
-  
-        pTab = pItem->pTab;
-        assert( pTab!=0 );
-        iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
-        assert( pTab->nCol>0 );
-        if( zTab ){
-          if( pItem->zAlias ){
-            char *zTabName = pItem->zAlias;
-            if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
-          }else{
-            char *zTabName = pTab->zName;
-            if( zTabName==0 || sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
-            if( zDb!=0 && sqlite3StrICmp(db->aDb[iDb].zName, zDb)!=0 ){
-              continue;
-            }
-          }
-        }
-        if( 0==(cntTab++) ){
-          pExpr->iTable = pItem->iCursor;
-          pSchema = pTab->pSchema;
-          pMatch = pItem;
-        }
-        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
-          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
-            const char *zColl = pTab->aCol[j].zColl;
-            IdList *pUsing;
-            cnt++;
-            pExpr->iTable = pItem->iCursor;
-            pMatch = pItem;
-            pSchema = pTab->pSchema;
-            /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
-            pExpr->iColumn = j==pTab->iPKey ? -1 : j;
-            pExpr->affinity = pTab->aCol[j].affinity;
-            if( (pExpr->flags & EP_ExpCollate)==0 ){
-              pExpr->pColl = sqlite3FindCollSeq(db, ENC(db), zColl,-1, 0);
-            }
-            if( i<pSrcList->nSrc-1 ){
-              if( pItem[1].jointype & JT_NATURAL ){
-                /* If this match occurred in the left table of a natural join,
-                ** then skip the right table to avoid a duplicate match */
-                pItem++;
-                i++;
-              }else if( (pUsing = pItem[1].pUsing)!=0 ){
-                /* If this match occurs on a column that is in the USING clause
-                ** of a join, skip the search of the right table of the join
-                ** to avoid a duplicate match there. */
-                int k;
-                for(k=0; k<pUsing->nId; k++){
-                  if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ){
-                    pItem++;
-                    i++;
-                    break;
-                  }
-                }
-              }
-            }
-            break;
-          }
-        }
-      }
-    }
-
-#ifndef SQLITE_OMIT_TRIGGER
-    /* If we have not already resolved the name, then maybe 
-    ** it is a new.* or old.* trigger argument reference
-    */
-    if( zDb==0 && zTab!=0 && cnt==0 && pParse->trigStack!=0 ){
-      TriggerStack *pTriggerStack = pParse->trigStack;
-      Table *pTab = 0;
-      if( pTriggerStack->newIdx != -1 && sqlite3StrICmp("new", zTab) == 0 ){
-        pExpr->iTable = pTriggerStack->newIdx;
-        assert( pTriggerStack->pTab );
-        pTab = pTriggerStack->pTab;
-      }else if( pTriggerStack->oldIdx != -1 && sqlite3StrICmp("old", zTab)==0 ){
-        pExpr->iTable = pTriggerStack->oldIdx;
-        assert( pTriggerStack->pTab );
-        pTab = pTriggerStack->pTab;
-      }
-
-      if( pTab ){ 
-        int iCol;
-        Column *pCol = pTab->aCol;
-
-        pSchema = pTab->pSchema;
-        cntTab++;
-        for(iCol=0; iCol < pTab->nCol; iCol++, pCol++) {
-          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
-            const char *zColl = pTab->aCol[iCol].zColl;
-            cnt++;
-            pExpr->iColumn = iCol==pTab->iPKey ? -1 : iCol;
-            pExpr->affinity = pTab->aCol[iCol].affinity;
-            if( (pExpr->flags & EP_ExpCollate)==0 ){
-              pExpr->pColl = sqlite3FindCollSeq(db, ENC(db), zColl,-1, 0);
-            }
-            pExpr->pTab = pTab;
-            break;
-          }
-        }
-      }
-    }
-#endif /* !defined(SQLITE_OMIT_TRIGGER) */
-
-    /*
-    ** Perhaps the name is a reference to the ROWID
-    */
-    if( cnt==0 && cntTab==1 && sqlite3IsRowid(zCol) ){
-      cnt = 1;
-      pExpr->iColumn = -1;
-      pExpr->affinity = SQLITE_AFF_INTEGER;
-    }
-
-    /*
-    ** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
-    ** might refer to an result-set alias.  This happens, for example, when
-    ** we are resolving names in the WHERE clause of the following command:
-    **
-    **     SELECT a+b AS x FROM table WHERE x<10;
-    **
-    ** In cases like this, replace pExpr with a copy of the expression that
-    ** forms the result set entry ("a+b" in the example) and return immediately.
-    ** Note that the expression in the result set should have already been
-    ** resolved by the time the WHERE clause is resolved.
-    */
-    if( cnt==0 && (pEList = pNC->pEList)!=0 && zTab==0 ){
-      for(j=0; j<pEList->nExpr; j++){
-        char *zAs = pEList->a[j].zName;
-        if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
-          Expr *pDup, *pOrig;
-          assert( pExpr->pLeft==0 && pExpr->pRight==0 );
-          assert( pExpr->pList==0 );
-          assert( pExpr->pSelect==0 );
-          pOrig = pEList->a[j].pExpr;
-          if( !pNC->allowAgg && ExprHasProperty(pOrig, EP_Agg) ){
-            sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs);
-            sqlite3_free(zCol);
-            return 2;
-          }
-          pDup = sqlite3ExprDup(db, pOrig);
-          if( pExpr->flags & EP_ExpCollate ){
-            pDup->pColl = pExpr->pColl;
-            pDup->flags |= EP_ExpCollate;
-          }
-          if( pExpr->span.dyn ) sqlite3_free((char*)pExpr->span.z);
-          if( pExpr->token.dyn ) sqlite3_free((char*)pExpr->token.z);
-          memcpy(pExpr, pDup, sizeof(*pExpr));
-          sqlite3_free(pDup);
-          cnt = 1;
-          pMatch = 0;
-          assert( zTab==0 && zDb==0 );
-          goto lookupname_end_2;
-        }
-      } 
-    }
-
-    /* Advance to the next name context.  The loop will exit when either
-    ** we have a match (cnt>0) or when we run out of name contexts.
-    */
-    if( cnt==0 ){
-      pNC = pNC->pNext;
-    }
-  }
-
-  /*
-  ** If X and Y are NULL (in other words if only the column name Z is
-  ** supplied) and the value of Z is enclosed in double-quotes, then
-  ** Z is a string literal if it doesn't match any column names.  In that
-  ** case, we need to return right away and not make any changes to
-  ** pExpr.
-  **
-  ** Because no reference was made to outer contexts, the pNC->nRef
-  ** fields are not changed in any context.
-  */
-  if( cnt==0 && zTab==0 && pColumnToken->z[0]=='"' ){
-    sqlite3_free(zCol);
-    return 0;
-  }
-
-  /*
-  ** cnt==0 means there was not match.  cnt>1 means there were two or
-  ** more matches.  Either way, we have an error.
-  */
-  if( cnt!=1 ){
-    char *z = 0;
-    char *zErr;
-    zErr = (char*)(cnt==0 ? "no such column: %s" : "ambiguous column name: %s");
-    if( zDb ){
-      sqlite3SetString(&z, zDb, ".", zTab, ".", zCol, (char*)0);
-    }else if( zTab ){
-      sqlite3SetString(&z, zTab, ".", zCol, (char*)0);
-    }else{
-      z = sqlite3StrDup(zCol);
-    }
-    if( z ){
-      sqlite3ErrorMsg(pParse, zErr, z);
-      sqlite3_free(z);
-      pTopNC->nErr++;
-    }else{
-      db->mallocFailed = 1;
-    }
-  }
-
-  /* If a column from a table in pSrcList is referenced, then record
-  ** this fact in the pSrcList.a[].colUsed bitmask.  Column 0 causes
-  ** bit 0 to be set.  Column 1 sets bit 1.  And so forth.  If the
-  ** column number is greater than the number of bits in the bitmask
-  ** then set the high-order bit of the bitmask.
-  */
-  if( pExpr->iColumn>=0 && pMatch!=0 ){
-    int n = pExpr->iColumn;
-    if( n>=sizeof(Bitmask)*8 ){
-      n = sizeof(Bitmask)*8-1;
-    }
-    assert( pMatch->iCursor==pExpr->iTable );
-    pMatch->colUsed |= ((Bitmask)1)<<n;
-  }
-
-lookupname_end:
-  /* Clean up and return
-  */
-  sqlite3_free(zDb);
-  sqlite3_free(zTab);
-  sqlite3ExprDelete(pExpr->pLeft);
-  pExpr->pLeft = 0;
-  sqlite3ExprDelete(pExpr->pRight);
-  pExpr->pRight = 0;
-  pExpr->op = TK_COLUMN;
-lookupname_end_2:
-  sqlite3_free(zCol);
-  if( cnt==1 ){
-    assert( pNC!=0 );
-    sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
-    if( pMatch && !pMatch->pSelect ){
-      pExpr->pTab = pMatch->pTab;
-    }
-    /* Increment the nRef value on all name contexts from TopNC up to
-    ** the point where the name matched. */
-    for(;;){
-      assert( pTopNC!=0 );
-      pTopNC->nRef++;
-      if( pTopNC==pNC ) break;
-      pTopNC = pTopNC->pNext;
-    }
-    return 0;
-  } else {
-    return 1;
-  }
-}
-
-/*
-** This routine is designed as an xFunc for walkExprTree().
-**
-** Resolve symbolic names into TK_COLUMN operators for the current
-** node in the expression tree.  Return 0 to continue the search down
-** the tree or 2 to abort the tree walk.
-**
-** This routine also does error checking and name resolution for
-** function names.  The operator for aggregate functions is changed
-** to TK_AGG_FUNCTION.
-*/
-static int nameResolverStep(void *pArg, Expr *pExpr){
-  NameContext *pNC = (NameContext*)pArg;
-  Parse *pParse;
-
-  if( pExpr==0 ) return 1;
-  assert( pNC!=0 );
-  pParse = pNC->pParse;
-
-  if( ExprHasAnyProperty(pExpr, EP_Resolved) ) return 1;
-  ExprSetProperty(pExpr, EP_Resolved);
-#ifndef NDEBUG
-  if( pNC->pSrcList && pNC->pSrcList->nAlloc>0 ){
-    SrcList *pSrcList = pNC->pSrcList;
-    int i;
-    for(i=0; i<pNC->pSrcList->nSrc; i++){
-      assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
-    }
-  }
-#endif
-  switch( pExpr->op ){
-    /* Double-quoted strings (ex: "abc") are used as identifiers if
-    ** possible.  Otherwise they remain as strings.  Single-quoted
-    ** strings (ex: 'abc') are always string literals.
-    */
-    case TK_STRING: {
-      if( pExpr->token.z[0]=='\'' ) break;
-      /* Fall thru into the TK_ID case if this is a double-quoted string */
-    }
-    /* A lone identifier is the name of a column.
-    */
-    case TK_ID: {
-      lookupName(pParse, 0, 0, &pExpr->token, pNC, pExpr);
-      return 1;
-    }
-  
-    /* A table name and column name:     ID.ID
-    ** Or a database, table and column:  ID.ID.ID
-    */
-    case TK_DOT: {
-      Token *pColumn;
-      Token *pTable;
-      Token *pDb;
-      Expr *pRight;
-
-      /* if( pSrcList==0 ) break; */
-      pRight = pExpr->pRight;
-      if( pRight->op==TK_ID ){
-        pDb = 0;
-        pTable = &pExpr->pLeft->token;
-        pColumn = &pRight->token;
-      }else{
-        assert( pRight->op==TK_DOT );
-        pDb = &pExpr->pLeft->token;
-        pTable = &pRight->pLeft->token;
-        pColumn = &pRight->pRight->token;
-      }
-      lookupName(pParse, pDb, pTable, pColumn, pNC, pExpr);
-      return 1;
-    }
-
-    /* Resolve function names
-    */
-    case TK_CONST_FUNC:
-    case TK_FUNCTION: {
-      ExprList *pList = pExpr->pList;    /* The argument list */
-      int n = pList ? pList->nExpr : 0;  /* Number of arguments */
-      int no_such_func = 0;       /* True if no such function exists */
-      int wrong_num_args = 0;     /* True if wrong number of arguments */
-      int is_agg = 0;             /* True if is an aggregate function */
-      int i;
-      int auth;                   /* Authorization to use the function */
-      int nId;                    /* Number of characters in function name */
-      const char *zId;            /* The function name. */
-      FuncDef *pDef;              /* Information about the function */
-      int enc = ENC(pParse->db);  /* The database encoding */
-
-      zId = (char*)pExpr->token.z;
-      nId = pExpr->token.n;
-      pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
-      if( pDef==0 ){
-        pDef = sqlite3FindFunction(pParse->db, zId, nId, -1, enc, 0);
-        if( pDef==0 ){
-          no_such_func = 1;
-        }else{
-          wrong_num_args = 1;
-        }
-      }else{
-        is_agg = pDef->xFunc==0;
-      }
-#ifndef SQLITE_OMIT_AUTHORIZATION
-      if( pDef ){
-        auth = sqlite3AuthCheck(pParse, SQLITE_FUNCTION, 0, pDef->zName, 0);
-        if( auth!=SQLITE_OK ){
-          if( auth==SQLITE_DENY ){
-            sqlite3ErrorMsg(pParse, "not authorized to use function: %s",
-                                    pDef->zName);
-            pNC->nErr++;
-          }
-          pExpr->op = TK_NULL;
-          return 1;
-        }
-      }
-#endif
-      if( is_agg && !pNC->allowAgg ){
-        sqlite3ErrorMsg(pParse, "misuse of aggregate function %.*s()", nId,zId);
-        pNC->nErr++;
-        is_agg = 0;
-      }else if( no_such_func ){
-        sqlite3ErrorMsg(pParse, "no such function: %.*s", nId, zId);
-        pNC->nErr++;
-      }else if( wrong_num_args ){
-        sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()",
-             nId, zId);
-        pNC->nErr++;
-      }
-      if( is_agg ){
-        pExpr->op = TK_AGG_FUNCTION;
-        pNC->hasAgg = 1;
-      }
-      if( is_agg ) pNC->allowAgg = 0;
-      for(i=0; pNC->nErr==0 && i<n; i++){
-        walkExprTree(pList->a[i].pExpr, nameResolverStep, pNC);
-      }
-      if( is_agg ) pNC->allowAgg = 1;
-      /* FIX ME:  Compute pExpr->affinity based on the expected return
-      ** type of the function 
-      */
-      return is_agg;
-    }
-#ifndef SQLITE_OMIT_SUBQUERY
-    case TK_SELECT:
-    case TK_EXISTS:
-#endif
-    case TK_IN: {
-      if( pExpr->pSelect ){
-        int nRef = pNC->nRef;
-#ifndef SQLITE_OMIT_CHECK
-        if( pNC->isCheck ){
-          sqlite3ErrorMsg(pParse,"subqueries prohibited in CHECK constraints");
-        }
-#endif
-        sqlite3SelectResolve(pParse, pExpr->pSelect, pNC);
-        assert( pNC->nRef>=nRef );
-        if( nRef!=pNC->nRef ){
-          ExprSetProperty(pExpr, EP_VarSelect);
-        }
-      }
-      break;
-    }
-#ifndef SQLITE_OMIT_CHECK
-    case TK_VARIABLE: {
-      if( pNC->isCheck ){
-        sqlite3ErrorMsg(pParse,"parameters prohibited in CHECK constraints");
-      }
-      break;
-    }
-#endif
-  }
-  return 0;
-}
-
-/*
-** This routine walks an expression tree and resolves references to
-** table columns.  Nodes of the form ID.ID or ID resolve into an
-** index to the table in the table list and a column offset.  The 
-** Expr.opcode for such nodes is changed to TK_COLUMN.  The Expr.iTable
-** value is changed to the index of the referenced table in pTabList
-** plus the "base" value.  The base value will ultimately become the
-** VDBE cursor number for a cursor that is pointing into the referenced
-** table.  The Expr.iColumn value is changed to the index of the column 
-** of the referenced table.  The Expr.iColumn value for the special
-** ROWID column is -1.  Any INTEGER PRIMARY KEY column is tried as an
-** alias for ROWID.
-**
-** Also resolve function names and check the functions for proper
-** usage.  Make sure all function names are recognized and all functions
-** have the correct number of arguments.  Leave an error message
-** in pParse->zErrMsg if anything is amiss.  Return the number of errors.
-**
-** If the expression contains aggregate functions then set the EP_Agg
-** property on the expression.
-*/
-int sqlite3ExprResolveNames( 
-  NameContext *pNC,       /* Namespace to resolve expressions in. */
-  Expr *pExpr             /* The expression to be analyzed. */
-){
-  int savedHasAgg;
-  if( pExpr==0 ) return 0;
-#if defined(SQLITE_TEST) || SQLITE_MAX_EXPR_DEPTH>0
-  if( (pExpr->nHeight+pNC->pParse->nHeight)>SQLITE_MAX_EXPR_DEPTH ){
-    sqlite3ErrorMsg(pNC->pParse, 
-       "Expression tree is too large (maximum depth %d)",
-       SQLITE_MAX_EXPR_DEPTH
-    );
-    return 1;
-  }
-  pNC->pParse->nHeight += pExpr->nHeight;
-#endif
-  savedHasAgg = pNC->hasAgg;
-  pNC->hasAgg = 0;
-  walkExprTree(pExpr, nameResolverStep, pNC);
-#if defined(SQLITE_TEST) || SQLITE_MAX_EXPR_DEPTH>0
-  pNC->pParse->nHeight -= pExpr->nHeight;
-#endif
-  if( pNC->nErr>0 ){
-    ExprSetProperty(pExpr, EP_Error);
-  }
-  if( pNC->hasAgg ){
-    ExprSetProperty(pExpr, EP_Agg);
-  }else if( savedHasAgg ){
-    pNC->hasAgg = 1;
-  }
-  return ExprHasProperty(pExpr, EP_Error);
-}
-
-/*
-** A pointer instance of this structure is used to pass information
-** through walkExprTree into codeSubqueryStep().
-*/
-typedef struct QueryCoder QueryCoder;
-struct QueryCoder {
-  Parse *pParse;       /* The parsing context */
-  NameContext *pNC;    /* Namespace of first enclosing query */
-};
-
-#ifdef SQLITE_TEST
-  int sqlite3_enable_in_opt = 1;
-#else
-  #define sqlite3_enable_in_opt 1
-#endif
-
-/*
-** This function is used by the implementation of the IN (...) operator.
-** It's job is to find or create a b-tree structure that may be used
-** either to test for membership of the (...) set or to iterate through
-** its members, skipping duplicates.
-**
-** The cursor opened on the structure (database table, database index 
-** or ephermal table) is stored in pX->iTable before this function returns.
-** The returned value indicates the structure type, as follows:
-**
-**   IN_INDEX_ROWID - The cursor was opened on a database table.
-**   IN_INDEX_INDEX - The cursor was opened on a database indec.
-**   IN_INDEX_EPH -   The cursor was opened on a specially created and
-**                    populated epheremal table.
-**
-** An existing structure may only be used if the SELECT is of the simple
-** form:
-**
-**     SELECT <column> FROM <table>
-**
-** If the mustBeUnique parameter is false, the structure will be used 
-** for fast set membership tests. In this case an epheremal table must 
-** be used unless <column> is an INTEGER PRIMARY KEY or an index can 
-** be found with <column> as its left-most column.
-**
-** If mustBeUnique is true, then the structure will be used to iterate
-** through the set members, skipping any duplicates. In this case an
-** epheremal table must be used unless the selected <column> is guaranteed
-** to be unique - either because it is an INTEGER PRIMARY KEY or it
-** is unique by virtue of a constraint or implicit index.
-*/
-#ifndef SQLITE_OMIT_SUBQUERY
-int sqlite3FindInIndex(Parse *pParse, Expr *pX, int mustBeUnique){
-  Select *p;
-  int eType = 0;
-  int iTab = pParse->nTab++;
-
-  /* The follwing if(...) expression is true if the SELECT is of the 
-  ** simple form:
-  **
-  **     SELECT <column> FROM <table>
-  **
-  ** If this is the case, it may be possible to use an existing table
-  ** or index instead of generating an epheremal table.
-  */
-  if( sqlite3_enable_in_opt
-   && (p=pX->pSelect) && !p->pPrior
-   && !p->isDistinct && !p->isAgg && !p->pGroupBy
-   && p->pSrc && p->pSrc->nSrc==1 && !p->pSrc->a[0].pSelect
-   && !p->pSrc->a[0].pTab->pSelect                                  
-   && p->pEList->nExpr==1 && p->pEList->a[0].pExpr->op==TK_COLUMN
-   && !p->pLimit && !p->pOffset && !p->pWhere
-  ){
-    sqlite3 *db = pParse->db;
-    Index *pIdx;
-    Expr *pExpr = p->pEList->a[0].pExpr;
-    int iCol = pExpr->iColumn;
-    Vdbe *v = sqlite3GetVdbe(pParse);
-
-    /* This function is only called from two places. In both cases the vdbe
-    ** has already been allocated. So assume sqlite3GetVdbe() is always
-    ** successful here.
-    */
-    assert(v);
-    if( iCol<0 ){
-      int iMem = pParse->nMem++;
-      int iAddr;
-      Table *pTab = p->pSrc->a[0].pTab;
-      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
-      sqlite3VdbeUsesBtree(v, iDb);
-
-      sqlite3VdbeAddOp(v, OP_MemLoad, iMem, 0);
-      iAddr = sqlite3VdbeAddOp(v, OP_If, 0, iMem);
-      sqlite3VdbeAddOp(v, OP_MemInt, 1, iMem);
-
-      sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
-      eType = IN_INDEX_ROWID;
-
-      sqlite3VdbeJumpHere(v, iAddr);
-    }else{
-      /* The collation sequence used by the comparison. If an index is to 
-      ** be used in place of a temp-table, it must be ordered according
-      ** to this collation sequence.
-      */
-      CollSeq *pReq = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pExpr);
-
-      /* Check that the affinity that will be used to perform the 
-      ** comparison is the same as the affinity of the column. If
-      ** it is not, it is not possible to use any index.
-      */
-      Table *pTab = p->pSrc->a[0].pTab;
-      char aff = comparisonAffinity(pX);
-      int affinity_ok = (pTab->aCol[iCol].affinity==aff||aff==SQLITE_AFF_NONE);
-
-      for(pIdx=pTab->pIndex; pIdx && eType==0 && affinity_ok; pIdx=pIdx->pNext){
-        if( (pIdx->aiColumn[0]==iCol)
-         && (pReq==sqlite3FindCollSeq(db, ENC(db), pIdx->azColl[0], -1, 0))
-         && (!mustBeUnique || (pIdx->nColumn==1 && pIdx->onError!=OE_None))
-        ){
-          int iDb;
-          int iMem = pParse->nMem++;
-          int iAddr;
-          char *pKey;
-  
-          pKey = (char *)sqlite3IndexKeyinfo(pParse, pIdx);
-          iDb = sqlite3SchemaToIndex(db, pIdx->pSchema);
-          sqlite3VdbeUsesBtree(v, iDb);
-
-          sqlite3VdbeAddOp(v, OP_MemLoad, iMem, 0);
-          iAddr = sqlite3VdbeAddOp(v, OP_If, 0, iMem);
-          sqlite3VdbeAddOp(v, OP_MemInt, 1, iMem);
-  
-          sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
-          VdbeComment((v, "# %s", pIdx->zName));
-          sqlite3VdbeOp3(v,OP_OpenRead,iTab,pIdx->tnum,pKey,P3_KEYINFO_HANDOFF);
-          eType = IN_INDEX_INDEX;
-          sqlite3VdbeAddOp(v, OP_SetNumColumns, iTab, pIdx->nColumn);
-
-          sqlite3VdbeJumpHere(v, iAddr);
-        }
-      }
-    }
-  }
-
-  if( eType==0 ){
-    sqlite3CodeSubselect(pParse, pX);
-    eType = IN_INDEX_EPH;
-  }else{
-    pX->iTable = iTab;
-  }
-  return eType;
-}
-#endif
-
-/*
-** Generate code for scalar subqueries used as an expression
-** and IN operators.  Examples:
-**
-**     (SELECT a FROM b)          -- subquery
-**     EXISTS (SELECT a FROM b)   -- EXISTS subquery
-**     x IN (4,5,11)              -- IN operator with list on right-hand side
-**     x IN (SELECT a FROM b)     -- IN operator with subquery on the right
-**
-** The pExpr parameter describes the expression that contains the IN
-** operator or subquery.
-*/
-#ifndef SQLITE_OMIT_SUBQUERY
-void sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){
-  int testAddr = 0;                       /* One-time test address */
-  Vdbe *v = sqlite3GetVdbe(pParse);
-  if( v==0 ) return;
-
-
-  /* This code must be run in its entirety every time it is encountered
-  ** if any of the following is true:
-  **
-  **    *  The right-hand side is a correlated subquery
-  **    *  The right-hand side is an expression list containing variables
-  **    *  We are inside a trigger
-  **
-  ** If all of the above are false, then we can run this code just once
-  ** save the results, and reuse the same result on subsequent invocations.
-  */
-  if( !ExprHasAnyProperty(pExpr, EP_VarSelect) && !pParse->trigStack ){
-    int mem = pParse->nMem++;
-    sqlite3VdbeAddOp(v, OP_MemLoad, mem, 0);
-    testAddr = sqlite3VdbeAddOp(v, OP_If, 0, 0);
-    assert( testAddr>0 || pParse->db->mallocFailed );
-    sqlite3VdbeAddOp(v, OP_MemInt, 1, mem);
-  }
-
-  switch( pExpr->op ){
-    case TK_IN: {
-      char affinity;
-      KeyInfo keyInfo;
-      int addr;        /* Address of OP_OpenEphemeral instruction */
-
-      affinity = sqlite3ExprAffinity(pExpr->pLeft);
-
-      /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
-      ** expression it is handled the same way. A virtual table is 
-      ** filled with single-field index keys representing the results
-      ** from the SELECT or the <exprlist>.
-      **
-      ** If the 'x' expression is a column value, or the SELECT...
-      ** statement returns a column value, then the affinity of that
-      ** column is used to build the index keys. If both 'x' and the
-      ** SELECT... statement are columns, then numeric affinity is used
-      ** if either column has NUMERIC or INTEGER affinity. If neither
-      ** 'x' nor the SELECT... statement are columns, then numeric affinity
-      ** is used.
-      */
-      pExpr->iTable = pParse->nTab++;
-      addr = sqlite3VdbeAddOp(v, OP_OpenEphemeral, pExpr->iTable, 0);
-      memset(&keyInfo, 0, sizeof(keyInfo));
-      keyInfo.nField = 1;
-      sqlite3VdbeAddOp(v, OP_SetNumColumns, pExpr->iTable, 1);
-
-      if( pExpr->pSelect ){
-        /* Case 1:     expr IN (SELECT ...)
-        **
-        ** Generate code to write the results of the select into the temporary
-        ** table allocated and opened above.
-        */
-        int iParm = pExpr->iTable +  (((int)affinity)<<16);
-        ExprList *pEList;
-        assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
-        if( sqlite3Select(pParse, pExpr->pSelect, SRT_Set, iParm, 0, 0, 0, 0) ){
-          return;
-        }
-        pEList = pExpr->pSelect->pEList;
-        if( pEList && pEList->nExpr>0 ){ 
-          keyInfo.aColl[0] = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft,
-              pEList->a[0].pExpr);
-        }
-      }else if( pExpr->pList ){
-        /* Case 2:     expr IN (exprlist)
-        **
-        ** For each expression, build an index key from the evaluation and
-        ** store it in the temporary table. If <expr> is a column, then use
-        ** that columns affinity when building index keys. If <expr> is not
-        ** a column, use numeric affinity.
-        */
-        int i;
-        ExprList *pList = pExpr->pList;
-		ExprList::ExprList_item *pItem;
-
-        if( !affinity ){
-          affinity = SQLITE_AFF_NONE;
-        }
-        keyInfo.aColl[0] = pExpr->pLeft->pColl;
-
-        /* Loop through each expression in <exprlist>. */
-        for(i=pList->nExpr, pItem=pList->a; i>0; i--, pItem++){
-          Expr *pE2 = pItem->pExpr;
-
-          /* If the expression is not constant then we will need to
-          ** disable the test that was generated above that makes sure
-          ** this code only executes once.  Because for a non-constant
-          ** expression we need to rerun this code each time.
-          */
-          if( testAddr>0 && !sqlite3ExprIsConstant(pE2) ){
-            sqlite3VdbeChangeToNoop(v, testAddr-1, 3);
-            testAddr = 0;
-          }
-
-          /* Evaluate the expression and insert it into the temp table */
-          sqlite3ExprCode(pParse, pE2);
-          sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &affinity, 1);
-          sqlite3VdbeAddOp(v, OP_IdxInsert, pExpr->iTable, 0);
-        }
-      }
-      sqlite3VdbeChangeP3(v, addr, (const char *)&keyInfo, P3_KEYINFO);
-      break;
-    }
-
-    case TK_EXISTS:
-    case TK_SELECT: {
-      /* This has to be a scalar SELECT.  Generate code to put the
-      ** value of this select in a memory cell and record the number
-      ** of the memory cell in iColumn.
-      */
-      static const Token one = { (u8*)"1", 0, 1 };
-      Select *pSel;
-      int iMem;
-      int sop;
-
-      pExpr->iColumn = iMem = pParse->nMem++;
-      pSel = pExpr->pSelect;
-      if( pExpr->op==TK_SELECT ){
-        sop = SRT_Mem;
-        sqlite3VdbeAddOp(v, OP_MemNull, iMem, 0);
-        VdbeComment((v, "# Init subquery result"));
-      }else{
-        sop = SRT_Exists;
-        sqlite3VdbeAddOp(v, OP_MemInt, 0, iMem);
-        VdbeComment((v, "# Init EXISTS result"));
-      }
-      sqlite3ExprDelete(pSel->pLimit);
-      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &one);
-      if( sqlite3Select(pParse, pSel, sop, iMem, 0, 0, 0, 0) ){
-        return;
-      }
-      break;
-    }
-  }
-
-  if( testAddr ){
-    sqlite3VdbeJumpHere(v, testAddr);
-  }
-
-  return;
-}
-#endif /* SQLITE_OMIT_SUBQUERY */
-
-/*
-** Duplicate an 8-byte value
-*/
-static char *dup8bytes(Vdbe *v, const char *in){
-  char *out = (char*)sqlite3DbMallocRaw(sqlite3VdbeDb(v), 8);
-  if( out ){
-    memcpy(out, in, 8);
-  }
-  return out;
-}
-
-/*
-** Generate an instruction that will put the floating point
-** value described by z[0..n-1] on the stack.
-**
-** The z[] string will probably not be zero-terminated.  But the 
-** z[n] character is guaranteed to be something that does not look
-** like the continuation of the number.
-*/
-static void codeReal(Vdbe *v, const char *z, int n, int negateFlag){
-  assert( z || v==0 || sqlite3VdbeDb(v)->mallocFailed );
-  if( z ){
-    double value;
-    char *zV;
-    assert( !isdigit(z[n]) );
-    sqlite3AtoF(z, &value);
-    if( negateFlag ) value = -value;
-    zV = dup8bytes(v, (char*)&value);
-    sqlite3VdbeOp3(v, OP_Real, 0, 0, zV, P3_REAL);
-  }
-}
-
-
-/*
-** Generate an instruction that will put the integer describe by
-** text z[0..n-1] on the stack.
-**
-** The z[] string will probably not be zero-terminated.  But the 
-** z[n] character is guaranteed to be something that does not look
-** like the continuation of the number.
-*/
-static void codeInteger(Vdbe *v, const char *z, int n, int negateFlag){
-  assert( z || v==0 || sqlite3VdbeDb(v)->mallocFailed );
-  if( z ){
-    int i;
-    assert( !isdigit(z[n]) );
-    if( sqlite3GetInt32(z, &i) ){
-      if( negateFlag ) i = -i;
-      sqlite3VdbeAddOp(v, OP_Integer, i, 0);
-    }else if( sqlite3FitsIn64Bits(z, negateFlag) ){
-      i64 value;
-      char *zV;
-      sqlite3Atoi64(z, &value);
-      if( negateFlag ) value = -value;
-      zV = dup8bytes(v, (char*)&value);
-      sqlite3VdbeOp3(v, OP_Int64, 0, 0, zV, P3_INT64);
-    }else{
-      codeReal(v, z, n, negateFlag);
-    }
-  }
-}
-
-
-/*
-** Generate code that will extract the iColumn-th column from
-** table pTab and push that column value on the stack.  There
-** is an open cursor to pTab in iTable.  If iColumn<0 then
-** code is generated that extracts the rowid.
-*/
-void sqlite3ExprCodeGetColumn(Vdbe *v, Table *pTab, int iColumn, int iTable){
-  if( iColumn<0 ){
-    int op = (pTab && IsVirtual(pTab)) ? OP_VRowid : OP_Rowid;
-    sqlite3VdbeAddOp(v, op, iTable, 0);
-  }else if( pTab==0 ){
-    sqlite3VdbeAddOp(v, OP_Column, iTable, iColumn);
-  }else{
-    int op = IsVirtual(pTab) ? OP_VColumn : OP_Column;
-    sqlite3VdbeAddOp(v, op, iTable, iColumn);
-    sqlite3ColumnDefault(v, pTab, iColumn);
-#ifndef SQLITE_OMIT_FLOATING_POINT
-    if( pTab->aCol[iColumn].affinity==SQLITE_AFF_REAL ){
-      sqlite3VdbeAddOp(v, OP_RealAffinity, 0, 0);
-    }
-#endif
-  }
-}
-
-/*
-** Generate code into the current Vdbe to evaluate the given
-** expression and leave the result on the top of stack.
-**
-** This code depends on the fact that certain token values (ex: TK_EQ)
-** are the same as opcode values (ex: OP_Eq) that implement the corresponding
-** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
-** the make process cause these values to align.  Assert()s in the code
-** below verify that the numbers are aligned correctly.
-*/
-void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
-  Vdbe *v = pParse->pVdbe;
-  int op;
-  int stackChng = 1;    /* Amount of change to stack depth */
-
-  if( v==0 ) return;
-  if( pExpr==0 ){
-    sqlite3VdbeAddOp(v, OP_Null, 0, 0);
-    return;
-  }
-  op = pExpr->op;
-  switch( op ){
-    case TK_AGG_COLUMN: {
-      AggInfo *pAggInfo = pExpr->pAggInfo;
-	  AggInfo::AggInfo_col *pCol = &pAggInfo->aCol[pExpr->iAgg];
-      if( !pAggInfo->directMode ){
-        sqlite3VdbeAddOp(v, OP_MemLoad, pCol->iMem, 0);
-        break;
-      }else if( pAggInfo->useSortingIdx ){
-        sqlite3VdbeAddOp(v, OP_Column, pAggInfo->sortingIdx,
-                              pCol->iSorterColumn);
-        break;
-      }
-      /* Otherwise, fall thru into the TK_COLUMN case */
-    }
-    case TK_COLUMN: {
-      if( pExpr->iTable<0 ){
-        /* This only happens when coding check constraints */
-        assert( pParse->ckOffset>0 );
-        sqlite3VdbeAddOp(v, OP_Dup, pParse->ckOffset-pExpr->iColumn-1, 1);
-      }else{
-        sqlite3ExprCodeGetColumn(v, pExpr->pTab, pExpr->iColumn, pExpr->iTable);
-      }
-      break;
-    }
-    case TK_INTEGER: {
-      codeInteger(v, (char*)pExpr->token.z, pExpr->token.n, 0);
-      break;
-    }
-    case TK_FLOAT: {
-      codeReal(v, (char*)pExpr->token.z, pExpr->token.n, 0);
-      break;
-    }
-    case TK_STRING: {
-      sqlite3DequoteExpr(pParse->db, pExpr);
-      sqlite3VdbeOp3(v,OP_String8, 0, 0, (char*)pExpr->token.z, pExpr->token.n);
-      break;
-    }
-    case TK_NULL: {
-      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
-      break;
-    }
-#ifndef SQLITE_OMIT_BLOB_LITERAL
-    case TK_BLOB: {
-      int n;
-      const char *z;
-      assert( TK_BLOB==OP_HexBlob );
-      n = pExpr->token.n - 3;
-      z = (char*)pExpr->token.z + 2;
-      assert( n>=0 );
-      if( n==0 ){
-        z = "";
-      }
-      sqlite3VdbeOp3(v, op, 0, 0, z, n);
-      break;
-    }
-#endif
-    case TK_VARIABLE: {
-      sqlite3VdbeAddOp(v, OP_Variable, pExpr->iTable, 0);
-      if( pExpr->token.n>1 ){
-        sqlite3VdbeChangeP3(v, -1, (char*)pExpr->token.z, pExpr->token.n);
-      }
-      break;
-    }
-    case TK_REGISTER: {
-      sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iTable, 0);
-      break;
-    }
-#ifndef SQLITE_OMIT_CAST
-    case TK_CAST: {
-      /* Expressions of the form:   CAST(pLeft AS token) */
-      int aff, to_op;
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      aff = sqlite3AffinityType(&pExpr->token);
-      to_op = aff - SQLITE_AFF_TEXT + OP_ToText;
-      assert( to_op==OP_ToText    || aff!=SQLITE_AFF_TEXT    );
-      assert( to_op==OP_ToBlob    || aff!=SQLITE_AFF_NONE    );
-      assert( to_op==OP_ToNumeric || aff!=SQLITE_AFF_NUMERIC );
-      assert( to_op==OP_ToInt     || aff!=SQLITE_AFF_INTEGER );
-      assert( to_op==OP_ToReal    || aff!=SQLITE_AFF_REAL    );
-      sqlite3VdbeAddOp(v, to_op, 0, 0);
-      stackChng = 0;
-      break;
-    }
-#endif /* SQLITE_OMIT_CAST */
-    case TK_LT:
-    case TK_LE:
-    case TK_GT:
-    case TK_GE:
-    case TK_NE:
-    case TK_EQ: {
-      assert( TK_LT==OP_Lt );
-      assert( TK_LE==OP_Le );
-      assert( TK_GT==OP_Gt );
-      assert( TK_GE==OP_Ge );
-      assert( TK_EQ==OP_Eq );
-      assert( TK_NE==OP_Ne );
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      sqlite3ExprCode(pParse, pExpr->pRight);
-      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, 0, 0);
-      stackChng = -1;
-      break;
-    }
-    case TK_AND:
-    case TK_OR:
-    case TK_PLUS:
-    case TK_STAR:
-    case TK_MINUS:
-    case TK_REM:
-    case TK_BITAND:
-    case TK_BITOR:
-    case TK_SLASH:
-    case TK_LSHIFT:
-    case TK_RSHIFT: 
-    case TK_CONCAT: {
-      assert( TK_AND==OP_And );
-      assert( TK_OR==OP_Or );
-      assert( TK_PLUS==OP_Add );
-      assert( TK_MINUS==OP_Subtract );
-      assert( TK_REM==OP_Remainder );
-      assert( TK_BITAND==OP_BitAnd );
-      assert( TK_BITOR==OP_BitOr );
-      assert( TK_SLASH==OP_Divide );
-      assert( TK_LSHIFT==OP_ShiftLeft );
-      assert( TK_RSHIFT==OP_ShiftRight );
-      assert( TK_CONCAT==OP_Concat );
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      sqlite3ExprCode(pParse, pExpr->pRight);
-      sqlite3VdbeAddOp(v, op, 0, 0);
-      stackChng = -1;
-      break;
-    }
-    case TK_UMINUS: {
-      Expr *pLeft = pExpr->pLeft;
-      assert( pLeft );
-      if( pLeft->op==TK_FLOAT || pLeft->op==TK_INTEGER ){
-        Token *p = &pLeft->token;
-        if( pLeft->op==TK_FLOAT ){
-          codeReal(v, (char*)p->z, p->n, 1);
-        }else{
-          codeInteger(v, (char*)p->z, p->n, 1);
-        }
-        break;
-      }
-      /* Fall through into TK_NOT */
-    }
-    case TK_BITNOT:
-    case TK_NOT: {
-      assert( TK_BITNOT==OP_BitNot );
-      assert( TK_NOT==OP_Not );
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      sqlite3VdbeAddOp(v, op, 0, 0);
-      stackChng = 0;
-      break;
-    }
-    case TK_ISNULL:
-    case TK_NOTNULL: {
-      int dest;
-      assert( TK_ISNULL==OP_IsNull );
-      assert( TK_NOTNULL==OP_NotNull );
-      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      dest = sqlite3VdbeCurrentAddr(v) + 2;
-      sqlite3VdbeAddOp(v, op, 1, dest);
-      sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);
-      stackChng = 0;
-      break;
-    }
-    case TK_AGG_FUNCTION: {
-      AggInfo *pInfo = pExpr->pAggInfo;
-      if( pInfo==0 ){
-        sqlite3ErrorMsg(pParse, "misuse of aggregate: %T",
-            &pExpr->span);
-      }else{
-        sqlite3VdbeAddOp(v, OP_MemLoad, pInfo->aFunc[pExpr->iAgg].iMem, 0);
-      }
-      break;
-    }
-    case TK_CONST_FUNC:
-    case TK_FUNCTION: {
-      ExprList *pList = pExpr->pList;
-      int nExpr = pList ? pList->nExpr : 0;
-      FuncDef *pDef;
-      int nId;
-      const char *zId;
-      int constMask = 0;
-      int i;
-      sqlite3 *db = pParse->db;
-      u8 enc = ENC(db);
-      CollSeq *pColl = 0;
-
-      zId = (char*)pExpr->token.z;
-      nId = pExpr->token.n;
-      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
-      assert( pDef!=0 );
-      nExpr = sqlite3ExprCodeExprList(pParse, pList);
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-      /* Possibly overload the function if the first argument is
-      ** a virtual table column.
-      **
-      ** For infix functions (LIKE, GLOB, REGEXP, and MATCH) use the
-      ** second argument, not the first, as the argument to test to
-      ** see if it is a column in a virtual table.  This is done because
-      ** the left operand of infix functions (the operand we want to
-      ** control overloading) ends up as the second argument to the
-      ** function.  The expression "A glob B" is equivalent to 
-      ** "glob(B,A).  We want to use the A in "A glob B" to test
-      ** for function overloading.  But we use the B term in "glob(B,A)".
-      */
-      if( nExpr>=2 && (pExpr->flags & EP_InfixFunc) ){
-        pDef = sqlite3VtabOverloadFunction(db, pDef, nExpr, pList->a[1].pExpr);
-      }else if( nExpr>0 ){
-        pDef = sqlite3VtabOverloadFunction(db, pDef, nExpr, pList->a[0].pExpr);
-      }
-#endif
-      for(i=0; i<nExpr && i<32; i++){
-        if( sqlite3ExprIsConstant(pList->a[i].pExpr) ){
-          constMask |= (1<<i);
-        }
-        if( pDef->needCollSeq && !pColl ){
-          pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
-        }
-      }
-      if( pDef->needCollSeq ){
-        if( !pColl ) pColl = pParse->db->pDfltColl; 
-        sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
-      }
-      sqlite3VdbeOp3(v, OP_Function, constMask, nExpr, (char*)pDef, P3_FUNCDEF);
-      stackChng = 1-nExpr;
-      break;
-    }
-#ifndef SQLITE_OMIT_SUBQUERY
-    case TK_EXISTS:
-    case TK_SELECT: {
-      if( pExpr->iColumn==0 ){
-        sqlite3CodeSubselect(pParse, pExpr);
-      }
-      sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0);
-      VdbeComment((v, "# load subquery result"));
-      break;
-    }
-    case TK_IN: {
-      int addr;
-      char affinity;
-      int ckOffset = pParse->ckOffset;
-      int eType;
-      int iLabel = sqlite3VdbeMakeLabel(v);
-
-      eType = sqlite3FindInIndex(pParse, pExpr, 0);
-
-      /* Figure out the affinity to use to create a key from the results
-      ** of the expression. affinityStr stores a static string suitable for
-      ** P3 of OP_MakeRecord.
-      */
-      affinity = comparisonAffinity(pExpr);
-
-      sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
-      pParse->ckOffset = (ckOffset ? (ckOffset+1) : 0);
-
-      /* Code the <expr> from "<expr> IN (...)". The temporary table
-      ** pExpr->iTable contains the values that make up the (...) set.
-      */
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      addr = sqlite3VdbeCurrentAddr(v);
-      sqlite3VdbeAddOp(v, OP_NotNull, -1, addr+4);            /* addr + 0 */
-      sqlite3VdbeAddOp(v, OP_Pop, 2, 0);
-      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
-      sqlite3VdbeAddOp(v, OP_Goto, 0, iLabel);
-      if( eType==IN_INDEX_ROWID ){
-        int iAddr = sqlite3VdbeCurrentAddr(v)+3;
-        sqlite3VdbeAddOp(v, OP_MustBeInt, 1, iAddr);
-        sqlite3VdbeAddOp(v, OP_NotExists, pExpr->iTable, iAddr);
-        sqlite3VdbeAddOp(v, OP_Goto, pExpr->iTable, iLabel);
-      }else{
-        sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &affinity, 1);   /* addr + 4 */
-        sqlite3VdbeAddOp(v, OP_Found, pExpr->iTable, iLabel);
-      }
-      sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);                  /* addr + 6 */
-      sqlite3VdbeResolveLabel(v, iLabel);
-
-      break;
-    }
-#endif
-    case TK_BETWEEN: {
-      Expr *pLeft = pExpr->pLeft;
-	  ExprList::ExprList_item *pLItem = pExpr->pList->a;
-      Expr *pRight = pLItem->pExpr;
-      sqlite3ExprCode(pParse, pLeft);
-      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
-      sqlite3ExprCode(pParse, pRight);
-      codeCompare(pParse, pLeft, pRight, OP_Ge, 0, 0);
-      sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
-      pLItem++;
-      pRight = pLItem->pExpr;
-      sqlite3ExprCode(pParse, pRight);
-      codeCompare(pParse, pLeft, pRight, OP_Le, 0, 0);
-      sqlite3VdbeAddOp(v, OP_And, 0, 0);
-      break;
-    }
-    case TK_UPLUS: {
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      stackChng = 0;
-      break;
-    }
-    case TK_CASE: {
-      int expr_end_label;
-      int jumpInst;
-      int nExpr;
-      int i;
-      ExprList *pEList;
-	  ExprList::ExprList_item *aListelem;
-
-      assert(pExpr->pList);
-      assert((pExpr->pList->nExpr % 2) == 0);
-      assert(pExpr->pList->nExpr > 0);
-      pEList = pExpr->pList;
-      aListelem = pEList->a;
-      nExpr = pEList->nExpr;
-      expr_end_label = sqlite3VdbeMakeLabel(v);
-      if( pExpr->pLeft ){
-        sqlite3ExprCode(pParse, pExpr->pLeft);
-      }
-      for(i=0; i<nExpr; i=i+2){
-        sqlite3ExprCode(pParse, aListelem[i].pExpr);
-        if( pExpr->pLeft ){
-          sqlite3VdbeAddOp(v, OP_Dup, 1, 1);
-          jumpInst = codeCompare(pParse, pExpr->pLeft, aListelem[i].pExpr,
-                                 OP_Ne, 0, 1);
-          sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
-        }else{
-          jumpInst = sqlite3VdbeAddOp(v, OP_IfNot, 1, 0);
-        }
-        sqlite3ExprCode(pParse, aListelem[i+1].pExpr);
-        sqlite3VdbeAddOp(v, OP_Goto, 0, expr_end_label);
-        sqlite3VdbeJumpHere(v, jumpInst);
-      }
-      if( pExpr->pLeft ){
-        sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
-      }
-      if( pExpr->pRight ){
-        sqlite3ExprCode(pParse, pExpr->pRight);
-      }else{
-        sqlite3VdbeAddOp(v, OP_Null, 0, 0);
-      }
-      sqlite3VdbeResolveLabel(v, expr_end_label);
-      break;
-    }
-#ifndef SQLITE_OMIT_TRIGGER
-    case TK_RAISE: {
-      if( !pParse->trigStack ){
-        sqlite3ErrorMsg(pParse,
-                       "RAISE() may only be used within a trigger-program");
-        return;
-      }
-      if( pExpr->iColumn!=OE_Ignore ){
-         assert( pExpr->iColumn==OE_Rollback ||
-                 pExpr->iColumn == OE_Abort ||
-                 pExpr->iColumn == OE_Fail );
-         sqlite3DequoteExpr(pParse->db, pExpr);
-         sqlite3VdbeOp3(v, OP_Halt, SQLITE_CONSTRAINT, pExpr->iColumn,
-                        (char*)pExpr->token.z, pExpr->token.n);
-      } else {
-         assert( pExpr->iColumn == OE_Ignore );
-         sqlite3VdbeAddOp(v, OP_ContextPop, 0, 0);
-         sqlite3VdbeAddOp(v, OP_Goto, 0, pParse->trigStack->ignoreJump);
-         VdbeComment((v, "# raise(IGNORE)"));
-      }
-      stackChng = 0;
-      break;
-    }
-#endif
-  }
-
-  if( pParse->ckOffset ){
-    pParse->ckOffset += stackChng;
-    assert( pParse->ckOffset );
-  }
-}
-
-#ifndef SQLITE_OMIT_TRIGGER
-/*
-** Generate code that evalutes the given expression and leaves the result
-** on the stack.  See also sqlite3ExprCode().
-**
-** This routine might also cache the result and modify the pExpr tree
-** so that it will make use of the cached result on subsequent evaluations
-** rather than evaluate the whole expression again.  Trivial expressions are
-** not cached.  If the expression is cached, its result is stored in a 
-** memory location.
-*/
-void sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr){
-  Vdbe *v = pParse->pVdbe;
-  VdbeOp *pOp;
-  int iMem;
-  int addr1, addr2;
-  if( v==0 ) return;
-  addr1 = sqlite3VdbeCurrentAddr(v);
-  sqlite3ExprCode(pParse, pExpr);
-  addr2 = sqlite3VdbeCurrentAddr(v);
-  if( addr2>addr1+1
-   || ((pOp = sqlite3VdbeGetOp(v, addr1))!=0 && pOp->opcode==OP_Function) ){
-    iMem = pExpr->iTable = pParse->nMem++;
-    sqlite3VdbeAddOp(v, OP_MemStore, iMem, 0);
-    pExpr->op = TK_REGISTER;
-  }
-}
-#endif
-
-/*
-** Generate code that pushes the value of every element of the given
-** expression list onto the stack.
-**
-** Return the number of elements pushed onto the stack.
-*/
-int sqlite3ExprCodeExprList(
-  Parse *pParse,     /* Parsing context */
-  ExprList *pList    /* The expression list to be coded */
-){
-	ExprList::ExprList_item *pItem;
-  int i, n;
-  if( pList==0 ) return 0;
-  n = pList->nExpr;
-  for(pItem=pList->a, i=n; i>0; i--, pItem++){
-    sqlite3ExprCode(pParse, pItem->pExpr);
-  }
-  return n;
-}
-
-/*
-** Generate code for a boolean expression such that a jump is made
-** to the label "dest" if the expression is true but execution
-** continues straight thru if the expression is false.
-**
-** If the expression evaluates to NULL (neither true nor false), then
-** take the jump if the jumpIfNull flag is true.
-**
-** This code depends on the fact that certain token values (ex: TK_EQ)
-** are the same as opcode values (ex: OP_Eq) that implement the corresponding
-** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
-** the make process cause these values to align.  Assert()s in the code
-** below verify that the numbers are aligned correctly.
-*/
-void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
-  Vdbe *v = pParse->pVdbe;
-  int op = 0;
-  int ckOffset = pParse->ckOffset;
-  if( v==0 || pExpr==0 ) return;
-  op = pExpr->op;
-  switch( op ){
-    case TK_AND: {
-      int d2 = sqlite3VdbeMakeLabel(v);
-      sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2, !jumpIfNull);
-      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
-      sqlite3VdbeResolveLabel(v, d2);
-      break;
-    }
-    case TK_OR: {
-      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
-      sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
-      break;
-    }
-    case TK_NOT: {
-      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
-      break;
-    }
-    case TK_LT:
-    case TK_LE:
-    case TK_GT:
-    case TK_GE:
-    case TK_NE:
-    case TK_EQ: {
-      assert( TK_LT==OP_Lt );
-      assert( TK_LE==OP_Le );
-      assert( TK_GT==OP_Gt );
-      assert( TK_GE==OP_Ge );
-      assert( TK_EQ==OP_Eq );
-      assert( TK_NE==OP_Ne );
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      sqlite3ExprCode(pParse, pExpr->pRight);
-      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
-      break;
-    }
-    case TK_ISNULL:
-    case TK_NOTNULL: {
-      assert( TK_ISNULL==OP_IsNull );
-      assert( TK_NOTNULL==OP_NotNull );
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      sqlite3VdbeAddOp(v, op, 1, dest);
-      break;
-    }
-    case TK_BETWEEN: {
-      /* The expression "x BETWEEN y AND z" is implemented as:
-      **
-      ** 1 IF (x < y) GOTO 3
-      ** 2 IF (x <= z) GOTO <dest>
-      ** 3 ...
-      */
-      int addr;
-      Expr *pLeft = pExpr->pLeft;
-      Expr *pRight = pExpr->pList->a[0].pExpr;
-      sqlite3ExprCode(pParse, pLeft);
-      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
-      sqlite3ExprCode(pParse, pRight);
-      addr = codeCompare(pParse, pLeft, pRight, OP_Lt, 0, !jumpIfNull);
-
-      pRight = pExpr->pList->a[1].pExpr;
-      sqlite3ExprCode(pParse, pRight);
-      codeCompare(pParse, pLeft, pRight, OP_Le, dest, jumpIfNull);
-
-      sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
-      sqlite3VdbeJumpHere(v, addr);
-      sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
-      break;
-    }
-    default: {
-      sqlite3ExprCode(pParse, pExpr);
-      sqlite3VdbeAddOp(v, OP_If, jumpIfNull, dest);
-      break;
-    }
-  }
-  pParse->ckOffset = ckOffset;
-}
-
-/*
-** Generate code for a boolean expression such that a jump is made
-** to the label "dest" if the expression is false but execution
-** continues straight thru if the expression is true.
-**
-** If the expression evaluates to NULL (neither true nor false) then
-** jump if jumpIfNull is true or fall through if jumpIfNull is false.
-*/
-void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
-  Vdbe *v = pParse->pVdbe;
-  int op = 0;
-  int ckOffset = pParse->ckOffset;
-  if( v==0 || pExpr==0 ) return;
-
-  /* The value of pExpr->op and op are related as follows:
-  **
-  **       pExpr->op            op
-  **       ---------          ----------
-  **       TK_ISNULL          OP_NotNull
-  **       TK_NOTNULL         OP_IsNull
-  **       TK_NE              OP_Eq
-  **       TK_EQ              OP_Ne
-  **       TK_GT              OP_Le
-  **       TK_LE              OP_Gt
-  **       TK_GE              OP_Lt
-  **       TK_LT              OP_Ge
-  **
-  ** For other values of pExpr->op, op is undefined and unused.
-  ** The value of TK_ and OP_ constants are arranged such that we
-  ** can compute the mapping above using the following expression.
-  ** Assert()s verify that the computation is correct.
-  */
-  op = ((pExpr->op+(TK_ISNULL&1))^1)-(TK_ISNULL&1);
-
-  /* Verify correct alignment of TK_ and OP_ constants
-  */
-  assert( pExpr->op!=TK_ISNULL || op==OP_NotNull );
-  assert( pExpr->op!=TK_NOTNULL || op==OP_IsNull );
-  assert( pExpr->op!=TK_NE || op==OP_Eq );
-  assert( pExpr->op!=TK_EQ || op==OP_Ne );
-  assert( pExpr->op!=TK_LT || op==OP_Ge );
-  assert( pExpr->op!=TK_LE || op==OP_Gt );
-  assert( pExpr->op!=TK_GT || op==OP_Le );
-  assert( pExpr->op!=TK_GE || op==OP_Lt );
-
-  switch( pExpr->op ){
-    case TK_AND: {
-      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
-      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
-      break;
-    }
-    case TK_OR: {
-      int d2 = sqlite3VdbeMakeLabel(v);
-      sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2, !jumpIfNull);
-      sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
-      sqlite3VdbeResolveLabel(v, d2);
-      break;
-    }
-    case TK_NOT: {
-      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
-      break;
-    }
-    case TK_LT:
-    case TK_LE:
-    case TK_GT:
-    case TK_GE:
-    case TK_NE:
-    case TK_EQ: {
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      sqlite3ExprCode(pParse, pExpr->pRight);
-      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
-      break;
-    }
-    case TK_ISNULL:
-    case TK_NOTNULL: {
-      sqlite3ExprCode(pParse, pExpr->pLeft);
-      sqlite3VdbeAddOp(v, op, 1, dest);
-      break;
-    }
-    case TK_BETWEEN: {
-      /* The expression is "x BETWEEN y AND z". It is implemented as:
-      **
-      ** 1 IF (x >= y) GOTO 3
-      ** 2 GOTO <dest>
-      ** 3 IF (x > z) GOTO <dest>
-      */
-      int addr;
-      Expr *pLeft = pExpr->pLeft;
-      Expr *pRight = pExpr->pList->a[0].pExpr;
-      sqlite3ExprCode(pParse, pLeft);
-      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
-      sqlite3ExprCode(pParse, pRight);
-      addr = sqlite3VdbeCurrentAddr(v);
-      codeCompare(pParse, pLeft, pRight, OP_Ge, addr+3, !jumpIfNull);
-
-      sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
-      sqlite3VdbeAddOp(v, OP_Goto, 0, dest);
-      pRight = pExpr->pList->a[1].pExpr;
-      sqlite3ExprCode(pParse, pRight);
-      codeCompare(pParse, pLeft, pRight, OP_Gt, dest, jumpIfNull);
-      break;
-    }
-    default: {
-      sqlite3ExprCode(pParse, pExpr);
-      sqlite3VdbeAddOp(v, OP_IfNot, jumpIfNull, dest);
-      break;
-    }
-  }
-  pParse->ckOffset = ckOffset;
-}
-
-/*
-** Do a deep comparison of two expression trees.  Return TRUE (non-zero)
-** if they are identical and return FALSE if they differ in any way.
-**
-** Sometimes this routine will return FALSE even if the two expressions
-** really are equivalent.  If we cannot prove that the expressions are
-** identical, we return FALSE just to be safe.  So if this routine
-** returns false, then you do not really know for certain if the two
-** expressions are the same.  But if you get a TRUE return, then you
-** can be sure the expressions are the same.  In the places where
-** this routine is used, it does not hurt to get an extra FALSE - that
-** just might result in some slightly slower code.  But returning
-** an incorrect TRUE could lead to a malfunction.
-*/
-int sqlite3ExprCompare(Expr *pA, Expr *pB){
-  int i;
-  if( pA==0||pB==0 ){
-    return pB==pA;
-  }
-  if( pA->op!=pB->op ) return 0;
-  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 0;
-  if( !sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 0;
-  if( !sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 0;
-  if( pA->pList ){
-    if( pB->pList==0 ) return 0;
-    if( pA->pList->nExpr!=pB->pList->nExpr ) return 0;
-    for(i=0; i<pA->pList->nExpr; i++){
-      if( !sqlite3ExprCompare(pA->pList->a[i].pExpr, pB->pList->a[i].pExpr) ){
-        return 0;
-      }
-    }
-  }else if( pB->pList ){
-    return 0;
-  }
-  if( pA->pSelect || pB->pSelect ) return 0;
-  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 0;
-  if( pA->op!=TK_COLUMN && pA->token.z ){
-    if( pB->token.z==0 ) return 0;
-    if( pB->token.n!=pA->token.n ) return 0;
-    if( sqlite3StrNICmp((char*)pA->token.z,(char*)pB->token.z,pB->token.n)!=0 ){
-      return 0;
-    }
-  }
-  return 1;
-}
-
-
-/*
-** Add a new element to the pAggInfo->aCol[] array.  Return the index of
-** the new element.  Return a negative number if malloc fails.
-*/
-static int addAggInfoColumn(sqlite3 *db, AggInfo *pInfo){
-  int i;
-  pInfo->aCol = (AggInfo::AggInfo_col*)sqlite3ArrayAllocate(
-       db,
-       pInfo->aCol,
-       sizeof(pInfo->aCol[0]),
-       3,
-       &pInfo->nColumn,
-       &pInfo->nColumnAlloc,
-       &i
-  );
-  return i;
-}    
-
-/*
-** Add a new element to the pAggInfo->aFunc[] array.  Return the index of
-** the new element.  Return a negative number if malloc fails.
-*/
-static int addAggInfoFunc(sqlite3 *db, AggInfo *pInfo){
-  int i;
-  pInfo->aFunc = (AggInfo::AggInfo_func*)sqlite3ArrayAllocate(
-       db, 
-       pInfo->aFunc,
-       sizeof(pInfo->aFunc[0]),
-       3,
-       &pInfo->nFunc,
-       &pInfo->nFuncAlloc,
-       &i
-  );
-  return i;
-}    
-
-/*
-** This is an xFunc for walkExprTree() used to implement 
-** sqlite3ExprAnalyzeAggregates().  See sqlite3ExprAnalyzeAggregates
-** for additional information.
-**
-** This routine analyzes the aggregate function at pExpr.
-*/
-static int analyzeAggregate(void *pArg, Expr *pExpr){
-  int i;
-  NameContext *pNC = (NameContext *)pArg;
-  Parse *pParse = pNC->pParse;
-  SrcList *pSrcList = pNC->pSrcList;
-  AggInfo *pAggInfo = pNC->pAggInfo;
-
-  switch( pExpr->op ){
-    case TK_AGG_COLUMN:
-    case TK_COLUMN: {
-      /* Check to see if the column is in one of the tables in the FROM
-      ** clause of the aggregate query */
-      if( pSrcList ){
-		  SrcList::SrcList_item *pItem = pSrcList->a;
-        for(i=0; i<pSrcList->nSrc; i++, pItem++){
-			AggInfo::AggInfo_col *pCol;
-          if( pExpr->iTable==pItem->iCursor ){
-            /* If we reach this point, it means that pExpr refers to a table
-            ** that is in the FROM clause of the aggregate query.  
-            **
-            ** Make an entry for the column in pAggInfo->aCol[] if there
-            ** is not an entry there already.
-            */
-			  int k=0;
-            pCol = pAggInfo->aCol;
-            for(k=0; k<pAggInfo->nColumn; k++, pCol++){
-              if( pCol->iTable==pExpr->iTable &&
-                  pCol->iColumn==pExpr->iColumn ){
-                break;
-              }
-            }
-            if( (k>=pAggInfo->nColumn)
-             && (k = addAggInfoColumn(pParse->db, pAggInfo))>=0 
-            ){
-              pCol = &pAggInfo->aCol[k];
-              pCol->pTab = pExpr->pTab;
-              pCol->iTable = pExpr->iTable;
-              pCol->iColumn = pExpr->iColumn;
-              pCol->iMem = pParse->nMem++;
-              pCol->iSorterColumn = -1;
-              pCol->pExpr = pExpr;
-              if( pAggInfo->pGroupBy ){
-                int j, n;
-                ExprList *pGB = pAggInfo->pGroupBy;
-				ExprList::ExprList_item *pTerm = pGB->a;
-                n = pGB->nExpr;
-                for(j=0; j<n; j++, pTerm++){
-                  Expr *pE = pTerm->pExpr;
-                  if( pE->op==TK_COLUMN && pE->iTable==pExpr->iTable &&
-                      pE->iColumn==pExpr->iColumn ){
-                    pCol->iSorterColumn = j;
-                    break;
-                  }
-                }
-              }
-              if( pCol->iSorterColumn<0 ){
-                pCol->iSorterColumn = pAggInfo->nSortingColumn++;
-              }
-            }
-            /* There is now an entry for pExpr in pAggInfo->aCol[] (either
-            ** because it was there before or because we just created it).
-            ** Convert the pExpr to be a TK_AGG_COLUMN referring to that
-            ** pAggInfo->aCol[] entry.
-            */
-            pExpr->pAggInfo = pAggInfo;
-            pExpr->op = TK_AGG_COLUMN;
-            pExpr->iAgg = k;
-            break;
-          } /* endif pExpr->iTable==pItem->iCursor */
-        } /* end loop over pSrcList */
-      }
-      return 1;
-    }
-    case TK_AGG_FUNCTION: {
-      /* The pNC->nDepth==0 test causes aggregate functions in subqueries
-      ** to be ignored */
-      if( pNC->nDepth==0 ){
-        /* Check to see if pExpr is a duplicate of another aggregate 
-        ** function that is already in the pAggInfo structure
-        */
-		  AggInfo::AggInfo_func *pItem = pAggInfo->aFunc;
-        for(i=0; i<pAggInfo->nFunc; i++, pItem++){
-          if( sqlite3ExprCompare(pItem->pExpr, pExpr) ){
-            break;
-          }
-        }
-        if( i>=pAggInfo->nFunc ){
-          /* pExpr is original.  Make a new entry in pAggInfo->aFunc[]
-          */
-          u8 enc = ENC(pParse->db);
-          i = addAggInfoFunc(pParse->db, pAggInfo);
-          if( i>=0 ){
-            pItem = &pAggInfo->aFunc[i];
-            pItem->pExpr = pExpr;
-            pItem->iMem = pParse->nMem++;
-            pItem->pFunc = sqlite3FindFunction(pParse->db,
-                   (char*)pExpr->token.z, pExpr->token.n,
-                   pExpr->pList ? pExpr->pList->nExpr : 0, enc, 0);
-            if( pExpr->flags & EP_Distinct ){
-              pItem->iDistinct = pParse->nTab++;
-            }else{
-              pItem->iDistinct = -1;
-            }
-          }
-        }
-        /* Make pExpr point to the appropriate pAggInfo->aFunc[] entry
-        */
-        pExpr->iAgg = i;
-        pExpr->pAggInfo = pAggInfo;
-        return 1;
-      }
-    }
-  }
-
-  /* Recursively walk subqueries looking for TK_COLUMN nodes that need
-  ** to be changed to TK_AGG_COLUMN.  But increment nDepth so that
-  ** TK_AGG_FUNCTION nodes in subqueries will be unchanged.
-  */
-  if( pExpr->pSelect ){
-    pNC->nDepth++;
-    walkSelectExpr(pExpr->pSelect, analyzeAggregate, pNC);
-    pNC->nDepth--;
-  }
-  return 0;
-}
-
-/*
-** Analyze the given expression looking for aggregate functions and
-** for variables that need to be added to the pParse->aAgg[] array.
-** Make additional entries to the pParse->aAgg[] array as necessary.
-**
-** This routine should only be called after the expression has been
-** analyzed by sqlite3ExprResolveNames().
-**
-** If errors are seen, leave an error message in zErrMsg and return
-** the number of errors.
-*/
-int sqlite3ExprAnalyzeAggregates(NameContext *pNC, Expr *pExpr){
-  int nErr = pNC->pParse->nErr;
-  walkExprTree(pExpr, analyzeAggregate, pNC);
-  return pNC->pParse->nErr - nErr;
-}
-
-/*
-** Call sqlite3ExprAnalyzeAggregates() for every expression in an
-** expression list.  Return the number of errors.
-**
-** If an error is found, the analysis is cut short.
-*/
-int sqlite3ExprAnalyzeAggList(NameContext *pNC, ExprList *pList){
-	ExprList::ExprList_item *pItem;
-  int i;
-  int nErr = 0;
-  if( pList ){
-    for(pItem=pList->a, i=0; nErr==0 && i<pList->nExpr; i++, pItem++){
-      nErr += sqlite3ExprAnalyzeAggregates(pNC, pItem->pExpr);
-    }
-  }
-  return nErr;
-}