mysql 删除多余重复记录
(stu表中的名字(name)是重复的)
问题:
在Mysql下执行:
在 Mysql下执行:
就现在的mysql版本(我用5.1)来说,不能先select出同一表中的某些值,再update这个表(在同一语句中)
解决:
在Mysql下执行:
MySql报错: You can't specify target table 'table name' for update in FROM clause
- delete from stu where name in (select name from stu group by name having count(name) > 1) and id not in (select id from stu group by name having count(name) > 1);
在 Mysql下执行:
是成功的。 注意:上面的两句话很矛盾啊。
- select id from stu where name in (select name from stu group by name having count(name) > 1) and id not in (select id from stu group by name having count(name) > 1);
就现在的mysql版本(我用5.1)来说,不能先select出同一表中的某些值,再update这个表(在同一语句中)
解决:
- create table tmp_table as select id from stu where name in (select name from stu group by name having count(name) > 1) and id not in (select id from stu group by name having count(name) > 1); delete from stu where id in (select id from tmp_table);
- drop table tmp_table;
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