SQLite

Check-in [af73fbca83]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Make sure min() and max() optimizations work for subqueries. Ticket #587. (CVS 1201)
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: af73fbca839f8cbe39c21f1f9e439fe9b79005c8
User & Date: drh 2004-01-30 02:01:04.000
Context
2004-01-30
14:49
Rework the VDBE data structures to combine string representations into the same structure with integer and floating point. This opens the door to significant optimizations. (CVS 1202) (check-in: c0faa1c67a user: drh tags: trunk)
02:01
Make sure min() and max() optimizations work for subqueries. Ticket #587. (CVS 1201) (check-in: af73fbca83 user: drh tags: trunk)
2004-01-27
17:46
Change permissions on the install-sh file to be executable. Ticket #582. (CVS 1200) (check-in: eafa714d1f user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/select.c.
︙︙
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22

**    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 1.149 2004/01/24 20:18:13 drh Exp $
*/
#include "sqliteInt.h"


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








|








8
9
10
11
12
13
14
15
16
17
18
19
20
21
22

**    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 1.150 2004/01/30 02:01:04 drh Exp $
*/
#include "sqliteInt.h"


/*
** Allocate a new Select structure and return a pointer to that
** structure.
︙︙
1895
1896
1897
1898
1899
1900
1901






1902
1903
1904
1905
1906
1907
1908

  ** The column names have already been generated in the calling function.
  */
  v = sqliteGetVdbe(pParse);
  if( v==0 ) return 0;
  if( eDest==SRT_Callback ){
    generateColumnTypes(pParse, p->pSrc, p->pEList);
  }







  /* Generating code to find the min or the max.  Basically all we have
  ** to do is find the first or the last entry in the chosen index.  If
  ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
  ** or last entry in the main table.
  */
  sqliteCodeVerifySchema(pParse, pTab->iDb);








>
>
>
>
>
>








1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914

  ** The column names have already been generated in the calling function.
  */
  v = sqliteGetVdbe(pParse);
  if( v==0 ) return 0;
  if( eDest==SRT_Callback ){
    generateColumnTypes(pParse, p->pSrc, p->pEList);
  }

  /* If the output is destined for a temporary table, open that table.
  */
  if( eDest==SRT_TempTable ){
    sqliteVdbeAddOp(v, OP_OpenTemp, iParm, 0);
  }

  /* Generating code to find the min or the max.  Basically all we have
  ** to do is find the first or the last entry in the chosen index.  If
  ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
  ** or last entry in the main table.
  */
  sqliteCodeVerifySchema(pParse, pTab->iDb);
︙︙
Changes to test/minmax.test.
︙︙
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing SELECT statements that contain
# aggregate min() and max() functions and which are handled as
# as a special case.
#
# $Id: minmax.test,v 1.6 2003/07/19 00:44:15 drh Exp $

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

do_test minmax-1.0 {
  execsql {
    BEGIN;








|








9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing SELECT statements that contain
# aggregate min() and max() functions and which are handled as
# as a special case.
#
# $Id: minmax.test,v 1.7 2004/01/30 02:01:05 drh Exp $

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

do_test minmax-1.0 {
  execsql {
    BEGIN;
︙︙
207
208
209
210
211
212
213
214


215






















216

  }
} {}
do_test minmax-6.7 {
  execsql {
    SELECT max(a) FROM t2 LIMIT 0
  }
} {}


























finish_test









>
>
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>


207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240

  }
} {}
do_test minmax-6.7 {
  execsql {
    SELECT max(a) FROM t2 LIMIT 0
  }
} {}

# Make sure the max(x) and min(x) optimizations work for nested
# queries.  Ticket #587.
#
do_test minmax-7.1 {
  execsql {
    SELECT max(x) FROM t1;
  }
} 20
do_test minmax-7.2 {
  execsql {
    SELECT * FROM (SELECT max(x) FROM t1);
  }
} 20
do_test minmax-7.3 {
  execsql {
    SELECT min(x) FROM t1;
  }
} 1
do_test minmax-7.4 {
  execsql {
    SELECT * FROM (SELECT min(x) FROM t1);
  }
} 1


finish_test