通过单个字段(name)删除:delete from user where id not in
(
select id from
(
select max(id) id from user group by name
) a
);
通过多个字段（name,age）删除:delete from user where id not in
(
select id from
(
select max(id) id from user group by name，age
) a
);
其实差不多啦，不过这么写sql效率很低，欢迎大家有什么高效的写法教给我，谢谢啦！