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mysql数据库 时间：2024-11-29 09:51:58
作者：文/会员上传
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1、使用mysql进行delete from操作时，若子查询的 FROM 字句和更新/删除对象使用同一张表，会出现错误。（相关推荐：MySQL教程）mysql> DELETE FROM 'tab' where id in (selec
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1、使用mysql进行delete from操作时，若子查询的 FROM 字句和更新/删除对象使用同一张表，会出现错误。（相关推荐：MySQL教程）
mysql> DELETE FROM 'tab' where id in (select min(id) from tag GROUP BY field1,field2 HAVING COUNT(id)>1);
error: You can't specify target table 'tab' for update in FROM clause.(不能为FROM子句中的更新指定目标表'tab')
针对“同一张表”这个限制，多数情况下都可以通过多加一层select 别名表来变通解决，像这样
DELETE FROM 'tab' where id in(select id from (select max(id) from 'tab' GROUP BY field1,field2 HAVING COUNT(id)>1) ids);
2.delete from table... 这其中table不能使用别名
mysql> delete from table a where a.id in (1,2);(语法错误)
mysql> select a.* from table a where a.id in (1,2);(执行成功)
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