Bug #103677 Max/Min for enum get different result whether using index

• Submitted: 13 May 2021 8:04
• Modified: 13 May 2021 8:22
• Reporter: Shenghui Wu
• Status: Verified
• Category: MySQL Server: Optimizer
• Severity: S3 (Non-critical)
• Version: 5.7.32, 8.0.22, 8.0.25, 5.7.34
• OS: Any
• CPU Architecture: Any

[13 May 2021 8:04] Shenghui Wu

Description:
Max/Min for enum get different result whether using index

How to repeat:
drop table t;
create table t(a enum('y','b','1','x','0','null') DEFAULT NULL,key(a));
insert into t values('y'),('b');
select min(a) from t;
MySQL [test]> select min(a) from t;
+--------+
| min(a) |
+--------+
| y      |
+--------+
1 row in set (0.000 sec)

drop table t;
create table t(a enum('y','b','1','x','0','null') DEFAULT NULL);
insert into t values('y'),('b');
select min(a) from t;
MySQL [test]> select min(a) from t;
+--------+
| min(a) |
+--------+
| b      |
+--------+
1 row in set (0.000 sec)

[13 May 2021 8:22] MySQL Verification Team

Hello Shenghui Wu,

Thank you for the report and test case.

regards,
Umesh