Bug #79902 Function GREATEST and LEAST works incorrectly with bigint unsigned value

• Submitted: 9 Jan 2016 15:46
• Modified: 19 Jan 2016 17:23
• Reporter: Su Dylan
• Status: Closed
• Category: MySQL Server: DML
• Severity: S2 (Serious)
• Version: 5.7.8, 5.5.48, 5.6.28, 5.7.10
• OS: Any
• CPU Architecture: Any

[9 Jan 2016 15:46] Su Dylan

Description:
Output:
=====
mysql> select greatest( 9223372036854775807 , 9223372036854775808 );
+-------------------------------------------------------+
| greatest( 9223372036854775807 , 9223372036854775808 ) |
+-------------------------------------------------------+
|                                   9223372036854775807 |
+-------------------------------------------------------+
1 row in set (0.00 sec)

mysql> select least( 9223372036854775807 , 9223372036854775808 );
+----------------------------------------------------+
| least( 9223372036854775807 , 9223372036854775808 ) |
+----------------------------------------------------+
|                               -9223372036854775808 |
+----------------------------------------------------+
1 row in set (0.00 sec)

mysql> select version();
+-----------+
| version() |
+-----------+
| 5.7.8-rc  |
+-----------+
1 row in set (0.00 sec)

Problem:
=====

How to repeat:
select greatest( 9223372036854775807 , 9223372036854775808 );
select least( 9223372036854775807 , 9223372036854775808 );

Suggested fix:
With bigint unsigned values, GREATEST/LEAST work as expected.

[11 Jan 2016 7:27] MySQL Verification Team

Hello Su Dylan,

Thank you for the report and test case.
Observed that 5.5.48/5.6.28/5.7.10 are affected.

Thanks,
Umesh

[19 Jan 2016 17:23] Paul DuBois

Noted in 5.8.0 changelog.

GREATEST() and LEAST() treated all integer input as signed.