SQLite

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is responsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.411 2009/07/31 06:14:52 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Trace output macros
*/
#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)

#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
  /* Analyze a term that is composed of two or more subterms connected by
  ** an OR operator.
  */
  else if( pExpr->op==TK_OR ){
    assert( pWC->op==TK_AND );
    exprAnalyzeOrTerm(pSrc, pWC, idxTerm);
    pTerm = &pWC->a[idxTerm];
  }
#endif /* SQLITE_OMIT_OR_OPTIMIZATION */

#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
  /* Add constraints to reduce the search space on a LIKE or GLOB
  ** operator.
  **

#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library. The focus
# is testing of where.c. More specifically, the focus is the optimization
# of WHERE clauses that feature the OR operator.
#
# $Id: where8.test,v 1.9 2009/07/31 06:14:52 danielk1977 Exp $

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

# Test organization:
#
#   where8-1.*: Tests to demonstrate simple cases work with a single table

      list
    } {}

    do_test where8-4.$A.$B.2 { lsort $R } [lsort $results($B)]
  }
  incr A
}

catch {unset results}
catch {unset A}
catch {unset B}

# At one point the following tests provoked an invalid write error (writing
# to memory that had already been freed). It was not possible to demonstrate
# that this bug could cause a query to return bad data.
# 
do_test where8-5.1 {
  db close
  sqlite3 db test.db
  sqlite3_db_config_lookaside db 0 0 0
  execsql {
    CREATE TABLE tA(
      a, b, c, d, e, f, g, h, 
      i, j, k, l, m, n, o, p
    );
  }
  execsql {
    SELECT * FROM tA WHERE
      a=1 AND b=2 AND c=3 AND d=4 AND e=5 AND f=6 AND g=7 AND h=8 AND
      i=1 AND j=2 AND k=3 AND l=4 AND m=5 AND n=6 AND o=7 AND
      (p = 1 OR p = 2 OR p = 3)
  }
} {}
do_test where8-5.2 {
  execsql {
    SELECT * FROM tA WHERE
      a=1 AND b=2 AND c=3 AND d=4 AND e=5 AND f=6 AND g=7 AND h=8 AND
      i=1 AND j=2 AND k=3 AND l=4 AND m=5 AND
      (p = 1 OR p = 2 OR p = 3) AND n=6 AND o=7
  }
} {}
do_test where8-5.3 {
  execsql {
    INSERT INTO tA VALUES(1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8); 
    CREATE UNIQUE INDEX tAI ON tA(p);
    CREATE TABLE tB(x);
    INSERT INTO tB VALUES('x');
  }
  execsql {
    SELECT a, x FROM tA LEFT JOIN tB ON (
      a=1 AND b=2 AND c=3 AND d=4 AND e=5 AND f=6 AND g=7 AND h=8 AND
      i=1 AND j=2 AND k=3 AND l=4 AND m=5 AND n=6 AND o=7 AND
      (p = 1 OR p = 2 OR p = 3)
    )
  }
} {1 {}}

finish_test