delete from Person where id in (select max(id) from person group by Email having count(*)>1);
在练习sql时 报错。
原因delete和select不能同时执行 使用笛卡尔积自关联表 筛选出条件
DELETE p1.* FROM Person p1, Person p2 WHERE p1.Email = p2.Email AND p1.Id > p2.Id