标签：select and The solution strong 一个 -- 查询 group
编写一个 SQL 查询，来删除 Person 表中所有重复的电子邮箱，重复的邮箱里只保留 Id 最小 的那个。
+----+------------------+ | Id | Email | +----+------------------+ | 1 | john@example.com | | 2 | bob@example.com | | 3 | john@example.com | +----+------------------+ Id 是这个表的主键。
例如，在运行你的查询语句之后，上面的 Person 表应返回以下几行:
+----+------------------+ | Id | Email | +----+------------------+ | 1 | john@example.com | | 2 | bob@example.com | +----+------------------+
delete
from Person
where Id not in
(
select p.min
from
(
select min(Id) as min
from Person
group by Email
) as p
)
-- other ways
delete p1 from person p1, person p2
where p1.email = p2.email and p1.id > p2.id;
标签：select and The solution strong 一个 -- 查询 group
原文地址：https://www.cnblogs.com/sumelt/p/10541389.html
