show full columns like should be case insensitive

[djshow832]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

mysql> create table t(id int);
Query OK, 0 rows affected (0.01 sec)

mysql> show full columns from t like 'id';
+-------+---------+-----------+------+------+---------+-------+---------------------------------+---------+
| Field | Type    | Collation | Null | Key  | Default | Extra | Privileges                      | Comment |
+-------+---------+-----------+------+------+---------+-------+---------------------------------+---------+
| id    | int(11) | NULL      | YES  |      | NULL    |       | select,insert,update,references |         |
+-------+---------+-----------+------+------+---------+-------+---------------------------------+---------+
1 row in set (0.00 sec)

mysql> show full columns from t like 'ID';
Empty set (0.00 sec)

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

In MySQL 8.0:

mysql> show full columns from t like 'ID';
+-------+------+-----------+------+-----+---------+-------+---------------------------------+---------+
| Field | Type | Collation | Null | Key | Default | Extra | Privileges                      | Comment |
+-------+------+-----------+------+-----+---------+-------+---------------------------------+---------+
| id    | int  | NULL      | YES  |     | NULL    |       | select,insert,update,references |         |
+-------+------+-----------+------+-----+---------+-------+---------------------------------+---------+
1 row in set (0.05 sec)

3. What did you see instead (Required)

mysql> show full columns from t like 'ID';
Empty set (0.00 sec)

This leads to incompatibility with some ecosystem tools.

4. What is your TiDB version? (Required)

master

[xiongjiwei]

similar with #26253

[Defined2014]

similar with #26253

Maybe we can close one of them.

[hawkingrei]

/assign

[github-actions]

Please check whether the issue should be labeled with 'affects-x.y' or 'fixes-x.y.z', and then remove 'needs-more-info' label.