Bug #355 DELETE FROM test WHERE NULL deletes all rows for MyISAM tables.

• Submitted: 1 May 2003 5:47
• Modified: 3 May 2003 9:20
• Reporter: Peter Zaitsev (Basic Quality Contributor)
• Status: Closed
• Category: MySQL Server
• Severity: S1 (Critical)
• Version: 4.0.13
• OS: Any (All)
• CPU Architecture: Any

[1 May 2003 5:47] Peter Zaitsev

Description:
DELETE FROM test WHERE NULL deletes all rows if test is MyISAM table but none 
if it is Innodb table. On other hand  SELECT * FROM test WHERE NULL returns no rows.

The same applies to any where clause which evaluates to NULL

How to repeat:
create table test(i int) type=MYISAM;
insert into test values (1);
select * from test where NULL;
delete from test where NULL;
select * from test;

[3 May 2003 8:17] Peter Zaitsev

I've tested similar bug report and discovered what bug happens even with this 
statements:

delete from test where 0;
delete from test where "1"="2";
delete from test where 1=2

Which makes bug even worse. 

It happens only with constant where clause.

[3 May 2003 9:20] Sergei Golubchik

fixed