如何删除表中多字段的重复项？（mysql）

Question

如果表格是这样的：

id | complains | zipcode
--------------------------
1  |  drinking |  10000
2  |  drinking |  10000
3  |  wasting  |  10000
4  |  wasting  |  10000
5  |  wasting  |  10000
6  |  wasting  |  10011
7  |  wasting  |  10011

我想得到：

---------------
drinking  10000
wasting   10000
wasting   10011
---------------

我应该如何编写SQL查询？我写的是这样的，但更新和选择不能在mySQL中同时执行。

delete from table where id not in (select max(id) from table group by complains, zipcode)

Answer 1

您可以使用子选择来欺骗MySQL：

delete from table 
where id not in 
(
     select * from (select max(id) from table group by complains, zipcode) x
)