SQLite

**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements.
**
** $Id: select.c,v 1.14 2000/06/06 22:13:55 drh Exp $
*/
#include "sqliteInt.h"

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

  }else 

  /* Construct a record from the query result, but instead of
  ** saving that record, use it as a key to delete elements from
  ** the temporary table iParm.
  */
  if( eDest==SRT_Except ){

    sqliteVdbeAddOp(v, OP_MakeRecord, nField, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_Delete, iParm, 0, 0, 0);
  }else 

  /* If we are creating a set for an "expr IN (SELECT ...)" construct,
  ** then there should be a single item on the stack.  Write this
  ** item into the set table with bogus data.
  */
  if( eDest==SRT_Set ){
    assert( pEList->nExpr==1 );
    sqliteVdbeAddOp(v, OP_String, 0, 0, "", 0);
    sqliteVdbeAddOp(v, OP_Put, iParm, 0, 0, 0);
  }else 


  /* If this is a scalar select that is part of an expression, then
  ** store the results in the appropriate memory cell and break out
  ** of the scan loop.
  */
  if( eDest==SRT_Mem ){
    assert( pEList->nExpr==1 );
    sqliteVdbeAddOp(v, OP_MemStore, iParm, 0, 0, 0);
    sqliteVdbeAddOp(v, OP_Goto, 0, iBreak, 0, 0);
  }else

  /* If none of the above, send the data to the callback function.
  */
  {

        sqliteVdbeAddOp(v, OP_Goto, 0, iCont, 0, 0);
        sqliteVdbeAddOp(v, OP_Close, unionTab, 0, 0, iBreak);
      }
      break;
    }
    case TK_INTERSECT: {
      int tab1, tab2;

      int iCont, iBreak;

      tab1 = pParse->nTab++;
      tab2 = pParse->nTab++;
      sqliteVdbeAddOp(v, OP_Open, tab1, 1, 0, 0);
      sqliteVdbeAddOp(v, OP_KeyAsData, tab1, 1, 0, 0);
      rc = sqliteSelect(pParse, pPrior, SRT_Union, tab1);

** inplicit conversion from one type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** function which does the work of interpreting a VDBE program.
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** $Id: vdbe.c,v 1.24 2000/06/06 22:13:55 drh Exp $
*/
#include "sqliteInt.h"
#include <unistd.h>

/*
** SQL is translated into a sequence of instructions to be
** executed by a virtual machine.  Each instruction is an instance

        int i = pOp->p1;
        int tos = ++p->tos;
        DbbeTable *pTab;

        if( NeedStack(p, p->tos) ) goto no_mem;
        if( i>=0 && i<p->nTable && (pTab = p->aTab[i].pTable)!=0 ){
          char *z = sqliteDbbeReadKey(pTab, 0);
          if( p->aTab[i].keyAsData ){
            p->zStack[tos] = z;
            p->aStack[tos].flags = STK_Str;
            p->aStack[tos].n = sqliteDbbeKeyLength(pTab);
          }else{
            memcpy(&p->aStack[tos].i, z, sizeof(int));
            p->aStack[tos].flags = STK_Int;
          }
        }
        break;
      }

      /* Opcode: Rewind P1 * *
      **
      ** The next use of the Key or Field or Next instruction for P1