Mysql从表中删除只出现一次

Question

我想从我的表中删除只出现一次的行。 我试过这个，但它给了我错误。

delete from trans where nol in (select nol from trans T1 group by T1.nol having count(*) = 1)

Answer 1

在MySQL中，您无法修改在SELECT部分​​中使用的同一个表。 要解决此问题，您需要将子查询包装到表别名中。

示例查询：

delete from trans 
where nol in (SELECT nol FROM
    (select nol from trans T1 group by T1.nol having count(*) = 1) t)