3 messages in com.mysql.lists.bugsRe: Bug in Union?!
FromSent OnAttachments
Georg Richter22 Dec 2002 07:07 
Sinisa Milivojevic23 Dec 2002 12:16 
Sinisa Milivojevic24 Dec 2002 10:41 
Subject:Re: Bug in Union?!
From:Sinisa Milivojevic (sin@mysql.com)
Date:12/24/2002 10:41:38 AM
List:com.mysql.lists.bugs

Georg Richter writes:

On Monday 23 December 2002 21:16, you wrote:

Hi!

I do not think that mixing UNION with and without braces should be allowed. For many reasons, although standard is not clear on this one.

Hello Sinisa,

unfortunately currently I don't have the time to test your fix (Kirsten's family is here during the christmas time, so I have to try not to spend too much time in front of my PC :). I'll check your fix after Dec 25th.

The sample also fails when I don't mix parenthesis/braces:

SELECT foo from bar limit 1,1 union select foo from bar limit 3,1 returns an empty resultset too.

I wish you and your family a merry christmas!

Regards

Georg

Hi Georg,

You were quite right, as you have hit a veritable bug.

One more reason, why forcing consistent usage / not-usage of braces is mandatory.

This is a fix for the bug.

==== sql/sql_union.cc 1.55 vs edited ===== *** /tmp/sql_union.cc-1.55-1877 Sat Dec 14 15:15:17 2002 --- edited/sql/sql_union.cc Tue Dec 24 20:36:12 2002 *************** *** 279,287 **** } if (!thd->fatal_error) // Check if EOM { ! offset_limit_cnt= global_parameters->offset_limit; ! select_limit_cnt= global_parameters->select_limit+ ! global_parameters->offset_limit; if (select_limit_cnt < global_parameters->select_limit) select_limit_cnt= HA_POS_ERROR; // no limit if (select_limit_cnt == HA_POS_ERROR) --- 279,288 ---- } if (!thd->fatal_error) // Check if EOM { ! SELECT_LEX *sl=thd->lex.current_select->master_unit()->first_select(); ! offset_limit_cnt= (sl->braces) ? global_parameters->offset_limit : 0; ! select_limit_cnt= (sl->braces) ? global_parameters->select_limit+ ! global_parameters->offset_limit : HA_POS_ERROR; if (select_limit_cnt < global_parameters->select_limit) select_limit_cnt= HA_POS_ERROR; // no limit if (select_limit_cnt == HA_POS_ERROR)

For the filter:

How-to-repeat:

Fix:

Happy Christmas to you and your family too !!!

-- __ ___ ___ ____ __ / |/ /_ __/ __/ __ \/ / Mr. Sinisa Milivojevic <sin@mysql.com> / /|_/ / // /\ \/ /_/ / /__ MySQL AB, Fulltime Developer /_/ /_/\_, /___/\___\_\___/ Larnaca, Cyprus <___/ www.mysql.com

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