SQLite

**    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 1.222 2005/01/17 08:57:09 danielk1977 Exp $
*/
#include "sqliteInt.h"


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

  int base;
  Vdbe *v;
  int seekOp;
  int cont;
  ExprList *pEList, *pList, eList;
  struct ExprList_item eListItem;
  SrcList *pSrc;


  /* Check to see if this query is a simple min() or max() query.  Return
  ** zero if it is  not.
  */
  if( p->pGroupBy || p->pHaving || p->pWhere ) return 0;
  pSrc = p->pSrc;
  if( pSrc->nSrc!=1 ) return 0;

  if( pSrc->a[0].pSelect==0 ){
    sqlite3OpenTableForReading(v, base, pTab);
  }
  cont = sqlite3VdbeMakeLabel(v);
  if( pIdx==0 ){
    sqlite3VdbeAddOp(v, seekOp, base, 0);
  }else{
    /* Even though the cursor used to open the index here is closed
    ** as soon as a single value has been read from it, allocate it
    ** using (pParse->nTab++) to prevent the cursor id from being 
    ** reused. This is important for statements of the form 
    ** "INSERT INTO x SELECT max() FROM x".
    */
    int iIdx;
    iIdx = pParse->nTab++;
    sqlite3VdbeAddOp(v, OP_Integer, pIdx->iDb, 0);
    sqlite3VdbeOp3(v, OP_OpenRead, iIdx, pIdx->tnum,
                   (char*)&pIdx->keyInfo, P3_KEYINFO);
    if( seekOp==OP_Rewind ){
      sqlite3VdbeAddOp(v, OP_String, 0, 0);
      sqlite3VdbeAddOp(v, OP_MakeRecord, 1, 0);
      seekOp = OP_MoveGt;
    }
    sqlite3VdbeAddOp(v, seekOp, iIdx, 0);
    sqlite3VdbeAddOp(v, OP_IdxRecno, iIdx, 0);
    sqlite3VdbeAddOp(v, OP_Close, iIdx, 0);
    sqlite3VdbeAddOp(v, OP_MoveGe, base, 0);
  }
  eList.nExpr = 1;
  memset(&eListItem, 0, sizeof(eListItem));
  eList.a = &eListItem;
  eList.a[0].pExpr = pExpr;
  selectInnerLoop(pParse, p, &eList, 0, 0, 0, -1, eDest, iParm, cont, cont, 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 implements regression tests for SQLite library.  The
# focus of this file is testing the INSERT statement.
#
# $Id: insert.test,v 1.22 2005/01/17 08:57:09 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Try to insert into a non-existant table.
#
do_test insert-1.1 {

  }
} {}
ifcapable {reindex} {
  do_test insert-6.7 {
    execsql REINDEX
  } {}
}

# Test that the special optimization for queries of the form 
# "SELECT max(x) FROM tbl" where there is an index on tbl(x) works with 
# INSERT statments.
do_test insert-7.1 {
  execsql {
    DROP TABLE t1;
    CREATE TABLE t1(a);
    INSERT INTO t1 VALUES(1);
    INSERT INTO t1 VALUES(2);
    CREATE INDEX i1 ON t1(a);
  }
} {}
do_test insert-7.2 {
  execsql {
    INSERT INTO t1 SELECT max(a) FROM t1;
  }
} {}
do_test insert-7.3 {
  execsql {
    SELECT a FROM t1;
  }
} {1 2 2}

integrity_check insert-99.0

finish_test