Description:
Sorry to bother you again.
At first sight this post is identical with Bug#85436 (https://bugs.mysql.com/bug.php?id=85436), while, it is not , maybe.
MySQL > create table t(a int, b int);
Query OK, 0 rows affected (0.05 sec)
MySQL > create table t1(a int, b int);
Query OK, 0 rows affected (0.04 sec)
MySQL > insert into t1 values(1,2);
Query OK, 1 row affected (0.04 sec)
MySQL > insert into t values(1,2);
Query OK, 1 row affected (0.04 sec)
OK, now, let us perform these statements one by one:
MySQL > select * from t, t;
ERROR 1066 (42000): Not unique table/alias: 't'
MySQL > select * from t1 as t, t;
ERROR 1066 (42000): Not unique table/alias: 't'
MySQL > select * from (select * from t1) t, (select * from t1) t;
ERROR 1066 (42000): Not unique table/alias: 't'
All failed. Let us move on please:
MySQL > select * from (select * from t1) as t, t;
+------+------+------+------+
| a | b | a | b |
+------+------+------+------+
| 1 | 2 | 1 | 2 |
+------+------+------+------+
1 row in set (0.03 sec)
It succeed.
After referring the doc of mysql5.6, I found nothing which can do me a favor to tell what is really going on here.
Would you please help me figure out what the rule and mechanism are when mysql resolves alias in a query ?
Is this a bug of mysql?
thank you very much.
How to repeat:
create table t(a int, b int);
create table t1(a int, b int);
insert into t1 values(1,2);
insert into t values(1,2);
select * from t, t;
select * from t1 as t, t;
select * from (select * from t1) t, (select * from t1) t;
select * from (select * from t1) as t, t;
