SQLite

**    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.c,v 1.216 2005/08/12 22:58:53 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**

*/
int sqlite3ExprCodeExprList(
  Parse *pParse,     /* Parsing context */
  ExprList *pList    /* The expression list to be coded */
){
  struct ExprList_item *pItem;
  int i, n;
  Vdbe *v;
  if( pList==0 ) return 0;
  v = sqlite3GetVdbe(pParse);
  n = pList->nExpr;
  for(pItem=pList->a, i=0; i<n; i++, pItem++){
    sqlite3ExprCode(pParse, pItem->pExpr);
  }
  return n;
}

/*
** Generate code for a boolean expression such that a jump is made

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.253 2005/07/08 17:13:47 drh Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.

** a join type, but put an error in the pParse structure.
*/
int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
  int jointype = 0;
  Token *apAll[3];
  Token *p;
  static const struct {
    const char *zKeyword;
    u8 nChar;
    u8 code;
  } keywords[] = {
    { "natural", 7, JT_NATURAL },
    { "left",    4, JT_LEFT|JT_OUTER },
    { "right",   5, JT_RIGHT|JT_OUTER },
    { "full",    4, JT_LEFT|JT_RIGHT|JT_OUTER },

*/
static void setToken(Token *p, const char *z){
  p->z = z;
  p->n = strlen(z);
  p->dyn = 0;
}











/*
** Add a term to the WHERE expression in *ppExpr that requires the
** zCol column to be equal in the two tables pTab1 and pTab2.
*/
static void addWhereTerm(
  const char *zCol,        /* Name of the column */
  const Table *pTab1,      /* First table */
  const char *zAlias1,     /* Alias for first table.  May be NULL */
  const Table *pTab2,      /* Second table */
  const char *zAlias2,     /* Alias for second table.  May be NULL */
  Expr **ppExpr            /* Add the equality term to this expression */
){
  Token dummy;
  Expr *pE1a, *pE1b, *pE1c;
  Expr *pE2a, *pE2b, *pE2c;
  Expr *pE;

  setToken(&dummy, zCol);
  pE1a = sqlite3Expr(TK_ID, 0, 0, &dummy);
  pE2a = sqlite3Expr(TK_ID, 0, 0, &dummy);
  if( zAlias1==0 ){
    zAlias1 = pTab1->zName;
  }
  setToken(&dummy, zAlias1);
  pE1b = sqlite3Expr(TK_ID, 0, 0, &dummy);
  if( zAlias2==0 ){
    zAlias2 = pTab2->zName;
  }
  setToken(&dummy, zAlias2);
  pE2b = sqlite3Expr(TK_ID, 0, 0, &dummy);
  pE1c = sqlite3Expr(TK_DOT, pE1b, pE1a, 0);
  pE2c = sqlite3Expr(TK_DOT, pE2b, pE2a, 0);
  pE = sqlite3Expr(TK_EQ, pE1c, pE2c, 0);
  ExprSetProperty(pE, EP_FromJoin);
  *ppExpr = sqlite3ExprAnd(*ppExpr, pE);
}

}

/*
** Insert code into "v" that will push the record on the top of the
** stack into the sorter.
*/
static void pushOntoSorter(Parse *pParse, Vdbe *v, ExprList *pOrderBy){
  int i;
  for(i=0; i<pOrderBy->nExpr; i++){
    sqlite3ExprCode(pParse, pOrderBy->a[i].pExpr);
  }
  sqlite3VdbeAddOp(v, OP_MakeRecord, pOrderBy->nExpr, 0);
  sqlite3VdbeAddOp(v, OP_SortInsert, 0, 0);
}

/*
** Add code to implement the OFFSET and LIMIT
*/

  */
  if( nColumn>0 ){
    for(i=0; i<nColumn; i++){
      sqlite3VdbeAddOp(v, OP_Column, srcTab, i);
    }
  }else{
    nColumn = pEList->nExpr;
    for(i=0; i<pEList->nExpr; i++){
      sqlite3ExprCode(pParse, pEList->a[i].pExpr);
    }
  }

  /* If the DISTINCT keyword was present on the SELECT statement
  ** and this row has been seen before, then do not make this row
  ** part of the result.
  */
  if( hasDistinct ){

#if NULL_ALWAYS_DISTINCT
    sqlite3VdbeAddOp(v, OP_IsNull, -pEList->nExpr, sqlite3VdbeCurrentAddr(v)+7);
#endif
    /* Deliberately leave the affinity string off of the following
    ** OP_MakeRecord */
    sqlite3VdbeAddOp(v, OP_MakeRecord, pEList->nExpr * -1, 0);
    sqlite3VdbeAddOp(v, OP_Distinct, distinct, sqlite3VdbeCurrentAddr(v)+3);
    sqlite3VdbeAddOp(v, OP_Pop, pEList->nExpr+1, 0);
    sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
    VdbeComment((v, "# skip indistinct records"));
    sqlite3VdbeAddOp(v, OP_IdxInsert, distinct, 0);
    if( pOrderBy==0 ){
      codeLimiter(v, p, iContinue, iBreak, nColumn);
    }
  }

        sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
        sqlite3VdbeAddOp(v, OP_Goto, 0, iBreak);
      }
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    /* Send the data to the callback function.


    */

    case SRT_Callback:
    case SRT_Sorter: {
      if( pOrderBy ){
        sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
        pushOntoSorter(pParse, v, pOrderBy);
      }else{
        assert( eDest==SRT_Callback );
        sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
      }
      break;
    }

    /* Invoke a subroutine to handle the results.  The subroutine itself
    ** is responsible for popping the results off of the stack.
    */
    case SRT_Subroutine: {
      if( pOrderBy ){
        sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
        pushOntoSorter(pParse, v, pOrderBy);
      }else{

        sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
      }
      break;
    }

#if !defined(SQLITE_OMIT_TRIGGER)
    /* Discard the results.  This is used for SELECT statements inside
    ** the body of a TRIGGER.  The purpose of such selects is to call

  ** processing.  
  */
  else{
    AggExpr *pAgg;
    int lbl1 = 0;
    pParse->fillAgg = 1;
    if( pGroupBy ){
      for(i=0; i<pGroupBy->nExpr; i++){
        sqlite3ExprCode(pParse, pGroupBy->a[i].pExpr);
      }
      /* No affinity string is attached to the following OP_MakeRecord 
      ** because we do not need to do any coercion of datatypes. */
      sqlite3VdbeAddOp(v, OP_MakeRecord, pGroupBy->nExpr, 0);
      lbl1 = sqlite3VdbeMakeLabel(v);
      sqlite3VdbeAddOp(v, OP_AggFocus, 0, lbl1);
    }
    for(i=0, pAgg=pParse->aAgg; i<pParse->nAgg; i++, pAgg++){