delete from tbl where id not in
(select id from (select id from tbl group by month having count(month)>1) as a)
mysql不支持在同一个表查询之后,做修改、删除 *** 作。
删除的思路是,
1、select id from tbl group by month having count(month)>1 找到需要保留的id
2、 select id from (select id from tblgroup by month having count(month)>1) as a
把需要保留的结果指定新的表名,找到保留id
3、执行删除 *** 作
select name from table --->假如你得到了 2,3,2,4那么select distinct name from table -->你肯定得到 2,3,4
你用什么语言得到的重复的数据?就用什么语言去除 再放到SQL里去
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