SQLite

  if( pExpr->op==TK_TRIGGER 
   && pExpr->iColumn==p->iCol 
   && pWalker->pParse->pTriggerTab==p->pTab
  ){
    renameTokenFind(pWalker->pParse, p, (void*)pExpr);
  }else if( pExpr->op==TK_COLUMN 
   && pExpr->iColumn==p->iCol 
   && p->pTab==pExpr->y.pTab
  ){
    renameTokenFind(pWalker->pParse, p, (void*)pExpr);
  }
  return WRC_Continue;
}

/*

}

/*
** Walker expression callback used by "RENAME TABLE". 
*/
static int renameTableExprCb(Walker *pWalker, Expr *pExpr){
  RenameCtx *p = pWalker->u.pRename;
  if( pExpr->op==TK_COLUMN && p->pTab==pExpr->y.pTab ){
    renameTokenFind(pWalker->pParse, p, (void*)&pExpr->y.pTab);
  }
  return WRC_Continue;
}

/*
** Walker select callback used by "RENAME TABLE". 
*/

  if( op==TK_REGISTER ) op = pExpr->op2;
#ifndef SQLITE_OMIT_CAST
  if( op==TK_CAST ){
    assert( !ExprHasProperty(pExpr, EP_IntValue) );
    return sqlite3AffinityType(pExpr->u.zToken, 0);
  }
#endif
  if( (op==TK_AGG_COLUMN || op==TK_COLUMN) && pExpr->y.pTab ){
    return sqlite3TableColumnAffinity(pExpr->y.pTab, pExpr->iColumn);
  }
  if( op==TK_SELECT_COLUMN ){
    assert( pExpr->pLeft->flags&EP_xIsSelect );
    return sqlite3ExprAffinity(
        pExpr->pLeft->x.pSelect->pEList->a[pExpr->iColumn].pExpr
    );
  }

  CollSeq *pColl = 0;
  Expr *p = pExpr;
  while( p ){
    int op = p->op;
    if( p->flags & EP_Generic ) break;
    if( (op==TK_AGG_COLUMN || op==TK_COLUMN
          || op==TK_REGISTER || op==TK_TRIGGER)
     && p->y.pTab!=0
    ){
      /* op==TK_REGISTER && p->y.pTab!=0 happens when pExpr was originally
      ** a TK_COLUMN but was previously evaluated and cached in a register */
      int j = p->iColumn;
      if( j>=0 ){
        const char *zColl = p->y.pTab->aCol[j].zColl;
        pColl = sqlite3FindCollSeq(db, ENC(db), zColl, 0);
      }
      break;
    }
    if( op==TK_CAST || op==TK_UPLUS ){
      p = p->pLeft;
      continue;

/*
** Recursively delete an expression tree.
*/
static SQLITE_NOINLINE void sqlite3ExprDeleteNN(sqlite3 *db, Expr *p){
  assert( p!=0 );
  /* Sanity check: Assert that the IntValue is non-negative if it exists */
  assert( !ExprHasProperty(p, EP_IntValue) || p->u.iValue>=0 );

  assert( !ExprHasProperty(p, EP_WinFunc) || p->y.pWin!=0 || db->mallocFailed );
  assert( p->op!=TK_FUNCTION || ExprHasProperty(p, EP_TokenOnly|EP_Reduced)
          || p->y.pWin==0 || ExprHasProperty(p, EP_WinFunc) );
#ifdef SQLITE_DEBUG
  if( ExprHasProperty(p, EP_Leaf) && !ExprHasProperty(p, EP_TokenOnly) ){
    assert( p->pLeft==0 );
    assert( p->pRight==0 );
    assert( p->x.pSelect==0 );
  }
#endif
  if( !ExprHasProperty(p, (EP_TokenOnly|EP_Leaf)) ){
    /* The Expr.x union is never used at the same time as Expr.pRight */
    assert( p->x.pList==0 || p->pRight==0 );
    if( p->pLeft && p->op!=TK_SELECT_COLUMN ) sqlite3ExprDeleteNN(db, p->pLeft);
    if( p->pRight ){
      sqlite3ExprDeleteNN(db, p->pRight);
    }else if( ExprHasProperty(p, EP_xIsSelect) ){
      sqlite3SelectDelete(db, p->x.pSelect);
    }else{
      sqlite3ExprListDelete(db, p->x.pList);
    }
    if( ExprHasProperty(p, EP_WinFunc) ){
      assert( p->op==TK_FUNCTION );
      sqlite3WindowDelete(db, p->y.pWin);
    }
  }
  if( ExprHasProperty(p, EP_MemToken) ) sqlite3DbFree(db, p->u.zToken);
  if( !ExprHasProperty(p, EP_Static) ){
    sqlite3DbFreeNN(db, p);
  }
}

static int dupedExprStructSize(Expr *p, int flags){
  int nSize;
  assert( flags==EXPRDUP_REDUCE || flags==0 ); /* Only one flag value allowed */
  assert( EXPR_FULLSIZE<=0xfff );
  assert( (0xfff & (EP_Reduced|EP_TokenOnly))==0 );
  if( 0==flags || p->op==TK_SELECT_COLUMN 
#ifndef SQLITE_OMIT_WINDOWFUNC
   || ExprHasProperty(p, EP_WinFunc)
#endif
  ){
    nSize = EXPR_FULLSIZE;
  }else{
    assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) );
    assert( !ExprHasProperty(p, EP_FromJoin) ); 
    assert( !ExprHasProperty(p, EP_MemToken) );

                       exprDup(db, p->pRight, EXPRDUP_REDUCE, &zAlloc) : 0;
      }
      if( pzBuffer ){
        *pzBuffer = zAlloc;
      }
    }else{
#ifndef SQLITE_OMIT_WINDOWFUNC
      if( ExprHasProperty(p, EP_WinFunc) ){


        pNew->y.pWin = sqlite3WindowDup(db, pNew, p->y.pWin);
        assert( ExprHasProperty(pNew, EP_WinFunc) );
      }
#endif /* SQLITE_OMIT_WINDOWFUNC */
      if( !ExprHasProperty(p, EP_TokenOnly|EP_Leaf) ){
        if( pNew->op==TK_SELECT_COLUMN ){
          pNew->pLeft = p->pLeft;
          assert( p->iColumn==0 || p->pRight==0 );
          assert( p->pRight==0  || p->pRight==p->pLeft );

    case TK_INTEGER:
    case TK_STRING:
    case TK_FLOAT:
    case TK_BLOB:
      return 0;
    case TK_COLUMN:
      return ExprHasProperty(p, EP_CanBeNull) ||
             p->y.pTab==0 ||  /* Reference to column of index on expression */
             (p->iColumn>=0 && p->y.pTab->aCol[p->iColumn].notNull==0);
    default:
      return 1;
  }
}

/*
** Return TRUE if the given expression is a constant which would be

        /* This COLUMN expression is really a constant due to WHERE clause
        ** constraints, and that constant is coded by the pExpr->pLeft
        ** expresssion.  However, make sure the constant has the correct
        ** datatype by applying the Affinity of the table column to the
        ** constant.
        */
        int iReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft,target);
        int aff = sqlite3TableColumnAffinity(pExpr->y.pTab, pExpr->iColumn);
        if( aff!=SQLITE_AFF_BLOB ){
          static const char zAff[] = "B\000C\000D\000E";
          assert( SQLITE_AFF_BLOB=='A' );
          assert( SQLITE_AFF_TEXT=='B' );
          if( iReg!=target ){
            sqlite3VdbeAddOp2(v, OP_SCopy, iReg, target);
            iReg = target;

          return pExpr->iColumn - pParse->iSelfTab;
        }else{
          /* Coding an expression that is part of an index where column names
          ** in the index refer to the table to which the index belongs */
          iTab = pParse->iSelfTab - 1;
        }
      }
      return sqlite3ExprCodeGetColumn(pParse, pExpr->y.pTab,
                               pExpr->iColumn, iTab, target,
                               pExpr->op2);
    }
    case TK_INTEGER: {
      codeInteger(pParse, pExpr, 0, target);
      return target;
    }

      u32 constMask = 0;     /* Mask of function arguments that are constant */
      int i;                 /* Loop counter */
      sqlite3 *db = pParse->db;  /* The database connection */
      u8 enc = ENC(db);      /* The text encoding used by this database */
      CollSeq *pColl = 0;    /* A collating sequence */

#ifndef SQLITE_OMIT_WINDOWFUNC
      if( ExprHasProperty(pExpr, EP_WinFunc) ){
        return pExpr->y.pWin->regResult;
      }
#endif

      if( ConstFactorOk(pParse) && sqlite3ExprIsConstantNotJoin(pExpr) ){
        /* SQL functions can be expensive. So try to move constant functions
        ** out of the inner loop, even if that means an extra OP_Copy. */
        return sqlite3ExprCodeAtInit(pParse, pExpr, -1);

      **
      ** Then p1 is interpreted as follows:
      **
      **   p1==0   ->    old.rowid     p1==3   ->    new.rowid
      **   p1==1   ->    old.a         p1==4   ->    new.a
      **   p1==2   ->    old.b         p1==5   ->    new.b       
      */
      Table *pTab = pExpr->y.pTab;
      int p1 = pExpr->iTable * (pTab->nCol+1) + 1 + pExpr->iColumn;

      assert( pExpr->iTable==0 || pExpr->iTable==1 );
      assert( pExpr->iColumn>=-1 && pExpr->iColumn<pTab->nCol );
      assert( pTab->iPKey<0 || pExpr->iColumn!=pTab->iPKey );
      assert( p1>=0 && p1<(pTab->nCol*2+2) );

      sqlite3VdbeAddOp2(v, OP_Param, p1, target);
      VdbeComment((v, "r[%d]=%s.%s", target,
        (pExpr->iTable ? "new" : "old"),
        (pExpr->iColumn<0 ? "rowid" : pExpr->y.pTab->aCol[pExpr->iColumn].zName)
      ));

#ifndef SQLITE_OMIT_FLOATING_POINT
      /* If the column has REAL affinity, it may currently be stored as an
      ** integer. Use OP_RealAffinity to make sure it is really real.
      **
      ** EVIDENCE-OF: R-60985-57662 SQLite will convert the value back to

      return 1;
    }
    return 2;
  }
  if( pA->op!=TK_COLUMN && pA->op!=TK_AGG_COLUMN && pA->u.zToken ){
    if( pA->op==TK_FUNCTION ){
      if( sqlite3StrICmp(pA->u.zToken,pB->u.zToken)!=0 ) return 2;
#ifndef SQLITE_OMIT_WINDOWFUNC
      /* Justification for the assert():
      ** window functions have p->op==TK_FUNCTION but aggregate functions
      ** have p->op==TK_AGG_FUNCTION.  So any comparison between an aggregate
      ** function and a window function should have failed before reaching
      ** this point.  And, it is not possible to have a window function and
      ** a scalar function with the same name and number of arguments.  So
      ** if we reach this point, either A and B both window functions or
      ** neither are a window functions. */
      assert( ExprHasProperty(pA,EP_WinFunc)==ExprHasProperty(pB,EP_WinFunc) );
      if( ExprHasProperty(pA,EP_WinFunc) ){
        if( sqlite3WindowCompare(pParse,pA->y.pWin,pB->y.pWin)!=0 ) return 2;
      }
#endif
    }else if( pA->op==TK_COLLATE ){
      if( sqlite3_stricmp(pA->u.zToken,pB->u.zToken)!=0 ) return 2;
    }else if( strcmp(pA->u.zToken,pB->u.zToken)!=0 ){
      return 2;
    }
  }
  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 2;
  if( ALWAYS((combinedFlags & EP_TokenOnly)==0) ){
    if( combinedFlags & EP_xIsSelect ) return 2;
    if( (combinedFlags & EP_FixedCol)==0
     && sqlite3ExprCompare(pParse, pA->pLeft, pB->pLeft, iTab) ) return 2;
    if( sqlite3ExprCompare(pParse, pA->pRight, pB->pRight, iTab) ) return 2;
    if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList, iTab) ) return 2;
    assert( (combinedFlags & EP_Reduced)==0 );
    if( pA->op!=TK_STRING && pA->op!=TK_TRUEFALSE ){
      if( pA->iColumn!=pB->iColumn ) return 2;
      if( pA->iTable!=pB->iTable 
       && (pA->iTable!=iTab || NEVER(pB->iTable>=0)) ) return 2;
    }















  }
  return 0;
}

/*
** Compare two ExprList objects.  Return 0 if they are identical and 
** non-zero if they differ in any way.

    case TK_GE:
      testcase( pExpr->op==TK_EQ );
      testcase( pExpr->op==TK_NE );
      testcase( pExpr->op==TK_LT );
      testcase( pExpr->op==TK_LE );
      testcase( pExpr->op==TK_GT );
      testcase( pExpr->op==TK_GE );
      if( (pExpr->pLeft->op==TK_COLUMN && IsVirtual(pExpr->pLeft->y.pTab))
       || (pExpr->pRight->op==TK_COLUMN && IsVirtual(pExpr->pRight->y.pTab))
      ){
       return WRC_Prune;
      }
    default:
      return WRC_Continue;
  }
}

                break;
              }
            }
            if( (k>=pAggInfo->nColumn)
             && (k = addAggInfoColumn(pParse->db, pAggInfo))>=0 
            ){
              pCol = &pAggInfo->aCol[k];
              pCol->pTab = pExpr->y.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;

  sqlite3 *db,      /* The database connection */
  Table *pTab,      /* The table whose column is desired */
  int iCursor,      /* The open cursor on the table */
  i16 iCol          /* The column that is wanted */
){
  Expr *pExpr = sqlite3Expr(db, TK_COLUMN, 0);
  if( pExpr ){
    pExpr->y.pTab = pTab;
    pExpr->iTable = iCursor;
    pExpr->iColumn = iCol;
  }
  return pExpr;
}

/*

      p->op = (u8)op;
      p->affinity = 0;
      p->flags = EP_Leaf;
      p->iAgg = -1;
      p->pLeft = p->pRight = 0;
      p->x.pList = 0;
      p->pAggInfo = 0;
      p->y.pTab = 0;
      p->op2 = 0;
      p->iTable = 0;
      p->iColumn = 0;



      p->u.zToken = (char*)&p[1];
      memcpy(p->u.zToken, t.z, t.n);
      p->u.zToken[t.n] = 0;
      if( sqlite3Isquote(p->u.zToken[0]) ){
        if( p->u.zToken[0]=='"' ) p->flags |= EP_DblQuoted;
        sqlite3Dequote(p->u.zToken);
      }

** 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 X
**                         (even if X is implied).
**    pExpr->iTable        Set to the cursor number for the table obtained
**                         from pSrcList.
**    pExpr->y.pTab        Points to the Table structure of X.Y (even if
**                         X and/or Y are implied.)
**    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 zDb variable is the name of the database (the "X").  This value may be

  assert( pNC );     /* the name context cannot be NULL. */
  assert( zCol );    /* The Z in X.Y.Z cannot be NULL */
  assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );

  /* Initialize the node to no-match */
  pExpr->iTable = -1;

  ExprSetVVAProperty(pExpr, EP_NoReduce);

  /* Translate the schema name in zDb into a pointer to the corresponding
  ** schema.  If not found, pSchema will remain NULL and nothing will match
  ** resulting in an appropriate error message toward the end of this routine
  */
  if( zDb ){

        if( zTab ){
          const char *zTabName = pItem->zAlias ? pItem->zAlias : pTab->zName;
          assert( zTabName!=0 );
          if( sqlite3StrICmp(zTabName, zTab)!=0 ){
            continue;
          }
          if( IN_RENAME_OBJECT && pItem->zAlias ){
            sqlite3RenameTokenRemap(pParse, 0, (void*)&pExpr->y.pTab);
          }
        }
        if( 0==(cntTab++) ){
          pMatch = pItem;
        }
        for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){

            pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;
            break;
          }
        }
      }
      if( pMatch ){
        pExpr->iTable = pMatch->iCursor;
        pExpr->y.pTab = pMatch->pTab;
        /* RIGHT JOIN not (yet) supported */
        assert( (pMatch->fg.jointype & JT_RIGHT)==0 );
        if( (pMatch->fg.jointype & JT_LEFT)!=0 ){
          ExprSetProperty(pExpr, EP_CanBeNull);
        }
        pSchema = pExpr->y.pTab->pSchema;
      }
    } /* if( pSrcList ) */

#if !defined(SQLITE_OMIT_TRIGGER) || !defined(SQLITE_OMIT_UPSERT)
    /* If we have not already resolved the name, then maybe 
    ** it is a new.* or old.* trigger argument reference.  Or
    ** maybe it is an excluded.* from an upsert.

        if( iCol<pTab->nCol ){
          cnt++;
#ifndef SQLITE_OMIT_UPSERT
          if( pExpr->iTable==2 ){
            testcase( iCol==(-1) );
            if( IN_RENAME_OBJECT ){
              pExpr->iColumn = iCol;
              pExpr->y.pTab = pTab;
              eNewExprOp = TK_COLUMN;
            }else{
              pExpr->iTable = pNC->uNC.pUpsert->regData + iCol;
              eNewExprOp = TK_REGISTER;
              ExprSetProperty(pExpr, EP_Alias);
            }
          }else

              testcase( iCol==32 );
              pParse->oldmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
            }else{
              testcase( iCol==31 );
              testcase( iCol==32 );
              pParse->newmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
            }
            pExpr->y.pTab = pTab;
            pExpr->iColumn = (i16)iCol;
            eNewExprOp = TK_TRIGGER;
#endif /* SQLITE_OMIT_TRIGGER */
          }
        }
      }
    }

  ** Because no reference was made to outer contexts, the pNC->nRef
  ** fields are not changed in any context.
  */
  if( cnt==0 && zTab==0 ){
    assert( pExpr->op==TK_ID );
    if( ExprHasProperty(pExpr,EP_DblQuoted) ){
      pExpr->op = TK_STRING;
      pExpr->y.pTab = 0;
      return WRC_Prune;
    }
    if( sqlite3ExprIdToTrueFalse(pExpr) ){
      return WRC_Prune;
    }
  }

** Allocate and return a pointer to an expression to load the column iCol
** from datasource iSrc in SrcList pSrc.
*/
Expr *sqlite3CreateColumnExpr(sqlite3 *db, SrcList *pSrc, int iSrc, int iCol){
  Expr *p = sqlite3ExprAlloc(db, TK_COLUMN, 0, 0);
  if( p ){
    struct SrcList_item *pItem = &pSrc->a[iSrc];
    p->y.pTab = pItem->pTab;
    p->iTable = pItem->iCursor;
    if( p->y.pTab->iPKey==iCol ){
      p->iColumn = -1;
    }else{
      p->iColumn = (ynVar)iCol;
      testcase( iCol==BMS );
      testcase( iCol==BMS-1 );
      pItem->colUsed |= ((Bitmask)1)<<(iCol>=BMS ? BMS-1 : iCol);
    }

    case TK_ROW: {
      SrcList *pSrcList = pNC->pSrcList;
      struct SrcList_item *pItem;
      assert( pSrcList && pSrcList->nSrc==1 );
      pItem = pSrcList->a;
      assert( HasRowid(pItem->pTab) && pItem->pTab->pSelect==0 );
      pExpr->op = TK_COLUMN;
      pExpr->y.pTab = pItem->pTab;
      pExpr->iTable = pItem->iCursor;
      pExpr->iColumn = -1;
      pExpr->affinity = SQLITE_AFF_INTEGER;
      break;
    }
#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT)
          && !defined(SQLITE_OMIT_SUBQUERY) */

        }
        zTable = pLeft->u.zToken;
        zColumn = pRight->u.zToken;
        if( IN_RENAME_OBJECT ){
          sqlite3RenameTokenRemap(pParse, (void*)pExpr, (void*)pRight);
        }
        if( IN_RENAME_OBJECT ){
          sqlite3RenameTokenRemap(pParse, (void*)&pExpr->y.pTab, (void*)pLeft);
        }
      }
      return lookupName(pParse, zDb, zTable, zColumn, pNC, pExpr);
    }

    /* Resolve function names
    */

      if( 0==IN_RENAME_OBJECT ){
#ifndef SQLITE_OMIT_WINDOWFUNC
        assert( is_agg==0 || (pDef->funcFlags & SQLITE_FUNC_MINMAX)
          || (pDef->xValue==0 && pDef->xInverse==0)
          || (pDef->xValue && pDef->xInverse && pDef->xSFunc && pDef->xFinalize)
        );
        if( pDef && pDef->xValue==0 && ExprHasProperty(pExpr, EP_WinFunc) ){
          sqlite3ErrorMsg(pParse, 
              "%.*s() may not be used as a window function", nId, zId
          );
          pNC->nErr++;
        }else if( 
              (is_agg && (pNC->ncFlags & NC_AllowAgg)==0)
           || (is_agg && (pDef->funcFlags&SQLITE_FUNC_WINDOW) && !pExpr->y.pWin)
           || (is_agg && pExpr->y.pWin && (pNC->ncFlags & NC_AllowWin)==0)
        ){
          const char *zType;
          if( (pDef->funcFlags & SQLITE_FUNC_WINDOW) || pExpr->y.pWin ){
            zType = "window";
          }else{
            zType = "aggregate";
          }
          sqlite3ErrorMsg(pParse, "misuse of %s function %.*s()",zType,nId,zId);
          pNC->nErr++;
          is_agg = 0;

        }else if( wrong_num_args ){
          sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()",
               nId, zId);
          pNC->nErr++;
        }
        if( is_agg ){
#ifndef SQLITE_OMIT_WINDOWFUNC
          pNC->ncFlags &= ~(pExpr->y.pWin ? NC_AllowWin : NC_AllowAgg);
#else
          pNC->ncFlags &= ~NC_AllowAgg;
#endif
        }
      }
      sqlite3WalkExprList(pWalker, pList);
      if( is_agg ){
#ifndef SQLITE_OMIT_WINDOWFUNC
        if( pExpr->y.pWin ){
          Select *pSel = pNC->pWinSelect;
          sqlite3WalkExprList(pWalker, pExpr->y.pWin->pPartition);
          sqlite3WalkExprList(pWalker, pExpr->y.pWin->pOrderBy);
          sqlite3WalkExpr(pWalker, pExpr->y.pWin->pFilter);
          sqlite3WindowUpdate(pParse, pSel->pWinDefn, pExpr->y.pWin, pDef);
          if( 0==pSel->pWin 
           || 0==sqlite3WindowCompare(pParse, pSel->pWin, pExpr->y.pWin) 
          ){
            pExpr->y.pWin->pNextWin = pSel->pWin;
            pSel->pWin = pExpr->y.pWin;
          }
          pNC->ncFlags |= NC_AllowWin;
        }else
#endif /* SQLITE_OMIT_WINDOWFUNC */
        {
          NameContext *pNC2 = pNC;
          pExpr->op = TK_AGG_FUNCTION;

    pItem->u.x.iOrderByCol = 0;
    if( sqlite3ResolveExprNames(pNC, pE) ){
      return 1;
    }
    for(j=0; j<pSelect->pEList->nExpr; j++){
      if( sqlite3ExprCompare(0, pE, pSelect->pEList->a[j].pExpr, -1)==0 ){
#ifndef SQLITE_OMIT_WINDOWFUNC
        if( ExprHasProperty(pE, EP_WinFunc) ){
          /* Since this window function is being changed into a reference
          ** to the same window function the result set, remove the instance
          ** of this window function from the Select.pWin list. */
          Window **pp;
          for(pp=&pSelect->pWin; *pp; pp=&(*pp)->pNextWin){
            if( *pp==pE->y.pWin ){
              *pp = (*pp)->pNextWin;
            }    
          }
        }
#endif
        pItem->u.x.iOrderByCol = j+1;
      }

  int i;
  int nDefer = 0;
  ExprList *pExtra = 0;
  for(i=0; i<pEList->nExpr; i++){
    struct ExprList_item *pItem = &pEList->a[i];
    if( pItem->u.x.iOrderByCol==0 ){
      Expr *pExpr = pItem->pExpr;
      Table *pTab = pExpr->y.pTab;
      if( pExpr->op==TK_COLUMN && pExpr->iColumn>=0 && pTab && !IsVirtual(pTab)
       && (pTab->aCol[pExpr->iColumn].colFlags & COLFLAG_SORTERREF)
      ){
        int j;
        for(j=0; j<nDefer; j++){
          if( pSort->aDefer[j].iCsr==pExpr->iTable ) break;
        }

              pPk = sqlite3PrimaryKeyIndex(pTab);
              nKey = pPk->nKeyCol;
            }
            for(k=0; k<nKey; k++){
              Expr *pNew = sqlite3PExpr(pParse, TK_COLUMN, 0, 0);
              if( pNew ){
                pNew->iTable = pExpr->iTable;
                pNew->y.pTab = pExpr->y.pTab;
                pNew->iColumn = pPk ? pPk->aiColumn[k] : -1;
                pExtra = sqlite3ExprListAppend(pParse, pExtra, pNew);
              }
            }
            pSort->aDefer[nDefer].pTab = pExpr->y.pTab;
            pSort->aDefer[nDefer].iCsr = pExpr->iTable;
            pSort->aDefer[nDefer].nKey = nKey;
            nDefer++;
          }
        }
        pItem->bSorterRef = 1;
      }

        ** This is not a problem, as the column type of "t1.col" is never
        ** used. When columnType() is called on the expression 
        ** "(SELECT t1.col)", the correct type is returned (see the TK_SELECT
        ** branch below.  */
        break;
      }

      assert( pTab && pExpr->y.pTab==pTab );
      if( pS ){
        /* The "table" is actually a sub-select or a view in the FROM clause
        ** of the SELECT statement. Return the declaration type and origin
        ** data for the result-set column of the sub-select.
        */
        if( iCol>=0 && iCol<pS->pEList->nExpr ){
          /* If iCol is less than zero, then the expression requests the

  srcName = (db->flags & SQLITE_ShortColNames)!=0 || fullName;
  sqlite3VdbeSetNumCols(v, pEList->nExpr);
  for(i=0; i<pEList->nExpr; i++){
    Expr *p = pEList->a[i].pExpr;

    assert( p!=0 );
    assert( p->op!=TK_AGG_COLUMN );  /* Agg processing has not run yet */
    assert( p->op!=TK_COLUMN || p->y.pTab!=0 ); /* Covering idx not yet coded */
    if( pEList->a[i].zName ){
      /* An AS clause always takes first priority */
      char *zName = pEList->a[i].zName;
      sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_TRANSIENT);
    }else if( srcName && p->op==TK_COLUMN ){
      char *zCol;
      int iCol = p->iColumn;
      pTab = p->y.pTab;
      assert( pTab!=0 );
      if( iCol<0 ) iCol = pTab->iPKey;
      assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
      if( iCol<0 ){
        zCol = "rowid";
      }else{
        zCol = pTab->aCol[iCol].zName;

        pColExpr = pColExpr->pRight;
        assert( pColExpr!=0 );
      }
      assert( pColExpr->op!=TK_AGG_COLUMN );
      if( pColExpr->op==TK_COLUMN ){
        /* For columns use the column name name */
        int iCol = pColExpr->iColumn;
        Table *pTab = pColExpr->y.pTab;
        assert( pTab!=0 );
        if( iCol<0 ) iCol = pTab->iPKey;
        zName = iCol>=0 ? pTab->aCol[iCol].zName : "rowid";
      }else if( pColExpr->op==TK_ID ){
        assert( !ExprHasProperty(pColExpr, EP_IntValue) );
        zName = pColExpr->u.zToken;
      }else{

                         ** TK_SELECT_COLUMN: column of the result vector */
  i16 iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
  i16 iRightJoinTable;   /* If EP_FromJoin, the right table of the join */
  u8 op2;                /* TK_REGISTER: original value of Expr.op
                         ** TK_COLUMN: the value of p5 for OP_Column
                         ** TK_AGG_FUNCTION: nesting depth */
  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
  union {
    Table *pTab;           /* TK_COLUMN: Table containing column. Can be NULL
                           ** for a column of an index on an expression */

    Window *pWin;          /* TK_FUNCTION: Window definition for the func */

  } y;
};

/*
** The following are the meanings of bits in the Expr.flags field.
*/
#define EP_FromJoin  0x000001 /* Originates in ON/USING clause of outer join */
#define EP_Agg       0x000002 /* Contains one or more aggregate functions */

#define EP_NoReduce  0x020000 /* Cannot EXPRDUP_REDUCE this Expr */
#define EP_Unlikely  0x040000 /* unlikely() or likelihood() function */
#define EP_ConstFunc 0x080000 /* A SQLITE_FUNC_CONSTANT or _SLOCHNG function */
#define EP_CanBeNull 0x100000 /* Can be null despite NOT NULL constraint */
#define EP_Subquery  0x200000 /* Tree contains a TK_SELECT operator */
#define EP_Alias     0x400000 /* Is an alias for a result set column */
#define EP_Leaf      0x800000 /* Expr.pLeft, .pRight, .u.pSelect all NULL */
#define EP_WinFunc  0x1000000 /* TK_FUNCTION with Expr.y.pWin set */

/*
** The EP_Propagate mask is a set of properties that automatically propagate
** upwards into parent nodes.
*/
#define EP_Propagate (EP_Collate|EP_Subquery|EP_HasFunc)

      Window *pWin;
      if( ExprHasProperty(pExpr, EP_TokenOnly) ){
        pFarg = 0;
        pWin = 0;
      }else{
        pFarg = pExpr->x.pList;
#ifndef SQLITE_OMIT_WINDOWFUNC
        pWin = pExpr->y.pWin;
#else
        pWin = 0;
#endif 
      }
      if( pExpr->op==TK_AGG_FUNCTION ){
        sqlite3TreeViewLine(pView, "AGG_FUNCTION%d %Q",
                             pExpr->op2, pExpr->u.zToken);

  void *pArg = 0;
  FuncDef *pNew;
  int rc = 0;

  /* Check to see the left operand is a column in a virtual table */
  if( NEVER(pExpr==0) ) return pDef;
  if( pExpr->op!=TK_COLUMN ) return pDef;
  pTab = pExpr->y.pTab;
  if( pTab==0 ) return pDef;
  if( !IsVirtual(pTab) ) return pDef;
  pVtab = sqlite3GetVTable(db, pTab)->pVtab;
  assert( pVtab!=0 );
  assert( pVtab->pModule!=0 );
  pMod = (sqlite3_module *)pVtab->pModule;
  if( pMod->xFindFunction==0 ) return pDef;

        continue;
      }else if( ExprHasProperty(pExpr, EP_xIsSelect) ){
        if( sqlite3WalkSelect(pWalker, pExpr->x.pSelect) ) return WRC_Abort;
      }else if( pExpr->x.pList ){
        if( sqlite3WalkExprList(pWalker, pExpr->x.pList) ) return WRC_Abort;
      }
#ifndef SQLITE_OMIT_WINDOWFUNC
      if( ExprHasProperty(pExpr, EP_WinFunc) ){
        Window *pWin = pExpr->y.pWin;
        if( sqlite3WalkExprList(pWalker, pWin->pPartition) ) return WRC_Abort;
        if( sqlite3WalkExprList(pWalker, pWin->pOrderBy) ) return WRC_Abort;
        if( sqlite3WalkExpr(pWalker, pWin->pFilter) ) return WRC_Abort;
      }
#endif
    }
    break;

*/
static int whereIndexExprTransNode(Walker *p, Expr *pExpr){
  IdxExprTrans *pX = p->u.pIdxTrans;
  if( sqlite3ExprCompare(0, pExpr, pX->pIdxExpr, pX->iTabCur)==0 ){
    pExpr->op = TK_COLUMN;
    pExpr->iTable = pX->iIdxCur;
    pExpr->iColumn = pX->iIdxCol;
    pExpr->y.pTab = 0;
    return WRC_Prune;
  }else{
    return WRC_Continue;
  }
}

/*

        */
        if( sqlite3Isdigit(zNew[0])
         || zNew[0]=='-'
         || (zNew[0]+1=='0' && iTo==1)
        ){
          if( pLeft->op!=TK_COLUMN 
           || sqlite3ExprAffinity(pLeft)!=SQLITE_AFF_TEXT 
           || IsVirtual(pLeft->y.pTab)  /* Value might be numeric */
          ){
            sqlite3ExprDelete(db, pPrefix);
            sqlite3ValueFree(pVal);
            return 0;
          }
        }
      }

    ** virtual table on their second argument, which is the same as
    ** the left-hand side operand in their in-fix form.
    **
    **       vtab_column MATCH expression
    **       MATCH(expression,vtab_column)
    */
    pCol = pList->a[1].pExpr;
    if( pCol->op==TK_COLUMN && IsVirtual(pCol->y.pTab) ){
      for(i=0; i<ArraySize(aOp); i++){
        if( sqlite3StrICmp(pExpr->u.zToken, aOp[i].zOp)==0 ){
          *peOp2 = aOp[i].eOp2;
          *ppRight = pList->a[0].pExpr;
          *ppLeft = pCol;
          return 1;
        }

    **      OVERLOADED(vtab_column,expression)
    **
    ** Historically, xFindFunction expected to see lower-case function
    ** names.  But for this use case, xFindFunction is expected to deal
    ** with function names in an arbitrary case.
    */
    pCol = pList->a[0].pExpr;
    if( pCol->op==TK_COLUMN && IsVirtual(pCol->y.pTab) ){
      sqlite3_vtab *pVtab;
      sqlite3_module *pMod;
      void (*xNotUsed)(sqlite3_context*,int,sqlite3_value**);
      void *pNotUsed;
      pVtab = sqlite3GetVTable(db, pCol->y.pTab)->pVtab;
      assert( pVtab!=0 );
      assert( pVtab->pModule!=0 );
      pMod = (sqlite3_module *)pVtab->pModule;
      if( pMod->xFindFunction!=0 ){
        i = pMod->xFindFunction(pVtab,2, pExpr->u.zToken, &xNotUsed, &pNotUsed);
        if( i>=SQLITE_INDEX_CONSTRAINT_FUNCTION ){
          *peOp2 = i;
          *ppRight = pList->a[1].pExpr;
          *ppLeft = pCol;
          return 1;
        }
      }
    }
  }else if( pExpr->op==TK_NE || pExpr->op==TK_ISNOT || pExpr->op==TK_NOTNULL ){
    int res = 0;
    Expr *pLeft = pExpr->pLeft;
    Expr *pRight = pExpr->pRight;
    if( pLeft->op==TK_COLUMN && IsVirtual(pLeft->y.pTab) ){
      res++;
    }
    if( pRight && pRight->op==TK_COLUMN && IsVirtual(pRight->y.pTab) ){
      res++;
      SWAP(Expr*, pLeft, pRight);
    }
    *ppLeft = pLeft;
    *ppRight = pRight;
    if( pExpr->op==TK_NE ) *peOp2 = SQLITE_INDEX_CONSTRAINT_NE;
    if( pExpr->op==TK_ISNOT ) *peOp2 = SQLITE_INDEX_CONSTRAINT_ISNOT;

                      pTab->zName, j);
      return;
    }
    pColRef = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0);
    if( pColRef==0 ) return;
    pColRef->iTable = pItem->iCursor;
    pColRef->iColumn = k++;
    pColRef->y.pTab = pTab;
    pTerm = sqlite3PExpr(pParse, TK_EQ, pColRef,
                         sqlite3ExprDup(pParse->db, pArgs->a[j].pExpr, 0));
    whereClauseInsert(pWC, pTerm, TERM_DYNAMIC);
  }
}

      if( i==nSrc ) return WRC_Continue;
    }
  }

  switch( pExpr->op ){

    case TK_FUNCTION:
      if( !ExprHasProperty(pExpr, EP_WinFunc) ){
        break;
      }else{
        Window *pWin;
        for(pWin=p->pWin; pWin; pWin=pWin->pNextWin){
          if( pExpr->y.pWin==pWin ){
            assert( pWin->pOwner==pExpr );
            return WRC_Prune;
          }
        }
      }
      /* Fall through.  */

}

/*
** Attach window object pWin to expression p.
*/
void sqlite3WindowAttach(Parse *pParse, Expr *p, Window *pWin){
  if( p ){
    assert( p->op==TK_FUNCTION );
    /* This routine is only called for the parser.  If pWin was not
    ** allocated due to an OOM, then the parser would fail before ever
    ** invoking this routine */
    if( ALWAYS(pWin) ){
      p->y.pWin = pWin;
      ExprSetProperty(p, EP_WinFunc);
      pWin->pOwner = p;
      if( p->flags & EP_Distinct ){
        sqlite3ErrorMsg(pParse,
           "DISTINCT is not supported for window functions");
      }
    }
  }else{

/*
** Allocate and return a duplicate of the Window object indicated by the
** third argument. Set the Window.pOwner field of the new object to
** pOwner.
*/
Window *sqlite3WindowDup(sqlite3 *db, Expr *pOwner, Window *p){
  Window *pNew = 0;
  if( ALWAYS(p) ){
    pNew = sqlite3DbMallocZero(db, sizeof(Window));
    if( pNew ){
      pNew->zName = sqlite3DbStrDup(db, p->zName);
      pNew->pFilter = sqlite3ExprDup(db, p->pFilter, 0);
      pNew->pPartition = sqlite3ExprListDup(db, p->pPartition, 0);
      pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy, 0);
      pNew->eType = p->eType;