Bug #102169 tinyint DIV a small value expression return wrong
Submitted: 7 Jan 9:42 Modified: 7 Jan 9:55
Reporter: zetao wei Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: DML Severity:S2 (Serious)
Version:8.0.18, 5.6.50, 5.7.32, 8.0.22 OS:Any
Assigned to: CPU Architecture:Any

[7 Jan 9:42] zetao wei
Description:

mysql> select (b DIV 0.0001 / 2) as x from t3 group by x;
+-----------+
| x         |
+-----------+
| 5000.0000 |
+-----------+

mysql> select (a DIV 0.0001 / 2) as x from t3 group by x order by x;
+----------+
| x        |
+----------+
| 999.9999 |
+----------+

The result is wrong when `Using temporary`.

I think the Field_new_decimal is overflow when the DIV expression has tinyint.

How to repeat:
create table t3 (a tinyint, b int);
insert into t3 values (1, 1);
select (a DIV 0.0001 / 2) as x from t3 group by x order by x;
[7 Jan 9:55] MySQL Verification Team
Hello zetao wei,

Thank you for the report and test case.

regards,
Umesh