Bug #103296 Aggregate function group by primary key/non-primary key has differnet result

• Submitted: 13 Apr 2021 5:35
• Modified: 13 Apr 2021 6:00
• Reporter: Shenghui Wu
• Status: Verified
• Category: MySQL Server: Optimizer
• Severity: S3 (Non-critical)
• Version: 8.0.22, 5.7.33, 8.0.23
• OS: Any
• CPU Architecture: Any

[13 Apr 2021 5:35] Shenghui Wu

Description:
Aggregate function group by primary key/non-primary key has differnet result

How to repeat:
create table t1(a int primary key, b set('Alice','Bob') DEFAULT NULL);
insert into t1 value(1,'Bob');
select max(b) + 0 from t1 group by a;
+------------+
| max(b) + 0 |
+------------+
|          0 |
+------------+

create table t2(a int, b set('Alice','Bob') DEFAULT NULL);
insert into t2 value(1,'Bob');
select max(b) + 0 from t2 group by a;
+------------+
| max(b) + 0 |
+------------+
|          2 |
+------------+

[13 Apr 2021 6:00] MySQL Verification Team

Hello Shenghui Wu,

Thank you for the report and test case.

regards,
Umesh