mysql锁错误还是错误？

Question

开始了:

mysql> LOCK TABLES radcheck WRITE;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT * FROM radcheck WHERE id NOT IN (
    ->     SELECT id FROM (
    ->         SELECT id FROM radcheck  WHERE attribute = 'Password' GROUP BY UserName HAVING COUNT(*) > 1
    ->      ) AS c
    -> );
ERROR 1100 (HY000): Table 'radcheck' was not locked with LOCK TABLES

WTF？

编辑

SET AUTOCOMMIT = 0
    -> ;
Query OK, 0 rows affected (0.00 sec)

mysql> LOCK TABLES radcheck WRITE;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT * FROM radcheck WHERE id NOT IN ( SELECT id FROM radcheck  WHERE attribute = 'Password' GROUP BY UserName HAVING COUNT(*) > 1 );
ERROR 1100 (HY000): Table 'radcheck' was not locked with LOCK TABLES



mysql> LOCK TABLES radcheck READ;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT * FROM radcheck WHERE id NOT IN ( SELECT id FROM radcheck  WHERE attribute = 'Password' GROUP BY UserName HAVING COUNT(*) > 1 );
ERROR 1100 (HY000): Table 'radcheck' was not locked with LOCK TABLES

pd:如果我没有锁定表,查询工作正常.pd:这只是一个例子,简化问题..在现实生活中是一个DELETE ...

Answer 1

当您使用锁表时,您需要锁定查询中的所有表.使用子查询时,它会创建一个表.而你没有锁定它.因为你得到错误.

参考:http: //dev.mysql.com/doc/refman/5.0/en/lock-tables.html

给内表一个别名

测试样本:

lock tables products as p1 write, products as p2 write ;
select product_id  from products as p1
where product_id  not in ( 
select product_id from products p2 where product_id in (1,2)
) 

也许你需要这个:

lock tables radcheck as r1 write, radcheck as r2 write ;

 SELECT * FROM radcheck r1 WHERE id NOT IN (
SELECT id FROM (
  SELECT id FROM radcheck r2 WHERE attribute = 'Password' GROUP BY UserName HAVING COUNT(*) > 1) AS c
 );