你好,游客 登录 注册 搜索
背景:
阅读新闻

MySQL Error 1093错误解决

[日期:2017-04-01] 来源:Linux社区  作者:corasql [字体: ]

场景演示:
mysql> create table test(id int,name varchar(12),primary key(id));
Query OK, 0 rows affected (0.04 sec)
mysql> insert into test values(1,'ttt');
Query OK, 1 row affected (0.00 sec)
mysql> insert into test values(2,'ttt');
Query OK, 1 row affected (0.00 sec)
mysql> commit;
Query OK, 0 rows affected (0.00 sec)
mysql>  update test set name='aaaa' where id  in (select id from test);
ERROR 1093 (HY000): You can't specify target table 'test' for update in FROM clause

官方说明:           
Error: 1093 SQLSTATE: HY000 (ER_UPDATE_TABLE_USED)
Message: You can't specify target table '%s' for update in FROM clause
This error occurs for attempts to select from and modify the same table within a single statement. If the select attempt occurs within a derived table, you can avoid this error by setting the derived_merge flag of the optimizer_switch system variable to force the subquery to be materialized into a temporary table, which effectively causes it to be a different table from the one modified. See Section 9.2.2.3, “Optimizing Derived Tables and View References”.

mysql不支持,在一条语句对同一个表,先查询再更新的操作。
解决方法1:改成sql
比如:利用临时表
mysql>  update test set name='aaaa' where id  in (select id from (select id from test)c);
Query OK, 2 rows affected (0.02 sec)
Rows matched: 2  Changed: 2  Warnings: 0

解决方法2:
官方说:可以通过设置optimizer_switch的 derived_merge参数来解决。
   
备注:Oracle是不会这个问题的

本文永久更新链接地址http://www.linuxidc.com/Linux/2017-04/142430.htm

linux
相关资讯       MySQL Error 1093 
本文评论   查看全部评论 (0)
表情: 表情 姓名: 字数

       

评论声明
  • 尊重网上道德,遵守中华人民共和国的各项有关法律法规
  • 承担一切因您的行为而直接或间接导致的民事或刑事法律责任
  • 本站管理人员有权保留或删除其管辖留言中的任意内容
  • 本站有权在网站内转载或引用您的评论
  • 参与本评论即表明您已经阅读并接受上述条款