dml: TiDB rejected valid select statement due to only_full_group_by while MySQL don't

[PragmaTwice]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

create table a(b integer);
SELECT c FROM(SELECT d c, d e FROM(SELECT 2 d FROM a) f) g GROUP BY e;

2. What did you expect to see? (Required)

Empty set (0.00 sec)

only_full_group_by is also enabled in MySQL.

3. What did you see instead (Required)

ERROR 1055 (42000): Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column '.g.' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

Interestingly, the column name '.g.' in this message is also weird.

4. What is your TiDB version? (Required)

+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version()                                                                            |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v5.1.0-alpha-167-ga8ad9b7d3
Edition: Community
Git Commit Hash: a8ad9b7d3aa53d0181422d2b22fa8d57b7d56db1
Git Branch: master
UTC Build Time: 2021-06-05 07:04:28
GoVersion: go1.16.4
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

[AilinKid]

winoros#7 In our latest feature branch, this case has been resolved.