Bug #35 Min function might return NULL for columns containing null and non-null values

• Submitted: 23 Jan 2003 18:26
• Modified: 15 Feb 2003 23:37
• Reporter: Igor Babaev
• Status: Closed
• Category: MySQL Server
• Severity: S3 (Non-critical)
• Version: 3.23
• OS: Any (any)
• Assigned to: Igor Babaev
• CPU Architecture: Any

[23 Jan 2003 18:26] Igor Babaev

Description:
Min aggregate function might return null value for columns than contain both
null and non-null values if there is an index(key) for this column.
Min must always return minimal non-null value.

How to repeat:
create table t1(a1 int, a2 char(3), key k1(a1), key k2(a2));
insert into t1 values(10,'aaa'); 
insert into t1 values(10,null);
insert into t1 values(10,'bbb');
insert into t1 values(20,'zzz'); 

select min(a2) from t1;

[15 Feb 2003 23:37] Michael Widenius

Fixed in 4.0.11;  Is not likely to be fixed in 3.23 as this is not a 
critical bug.