mysql メモ ユーザ変数

mysql> SELECT hoge.acl INTO @xacl FROM hoge WHERE id = 800;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> select @xacl;
+-------+
| @xacl |
+-------+
| NULL  |
+-------+
1 row in set (0.00 sec)

mysql> select @aaaaa;
+--------+
| @aaaaa |
+--------+
| NULL   |
+--------+
1 row in set (0.00 sec)

mysql> set @aaaaa = 'hoge';
Query OK, 0 rows affected (0.00 sec)

mysql> select @aaaaa;
+--------+
| @aaaaa |
+--------+
| hoge   |
+--------+
1 row in set (0.00 sec)

mysql> set @aaaaa = NULL;
Query OK, 0 rows affected (0.00 sec)

mysql> select @aaaaa;
+--------+
| @aaaaa |
+--------+
| NULL   |
+--------+
1 row in set (0.00 sec)