wrong Not unique table/alias error report

[xiongjiwei]

Bug Report

Please answer these questions before submitting your issue. Thanks!

same with #24550

1. Minimal reproduce step (Required)

create database db1;
create database db2;

-- both in db1 and db2
create table t(a int);
insert into t values (1);

use db1

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

mysql> select * from t, db2.t as t;
+------+------+
| a    | a    |
+------+------+
|    2 |    1 |
+------+------+
1 row in set (0.00 sec)

3. What did you see instead (Required)

mysql> select * from t, db2.t as t;
ERROR 1066 (42000): Not unique table/alias: 't'

4. What is your TiDB version? (Required)

[ichn-hu]

/unlabel sig/execution

[AilinKid]

use db1 & use db2 will contribute to different result in MySQL 8.0

mysql> use db2;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> explain select * from t, db2.t as t;
ERROR 1066 (42000): Not unique table/alias: 't'

[AilinKid]

seems MySQL will use the schema name as a part of resolving duplicates.

[winoros]

We reject this behavior of the MySQL's
TiDB would throw error for both cases.