【Leetcode】简单题：查找重复的电子邮箱

查找重复的电子邮箱

SQL架构

Create table If Not Exists Person (id int, email varchar(255))
Truncate table Person
insert into Person (id, email) values ('1', 'a@b.com')
insert into Person (id, email) values ('2', 'c@d.com')
insert into Person (id, email) values ('3', 'a@b.com')

编写一个 SQL 查询，查找 Person 表中所有重复的电子邮箱。

AC代码

select Email from Person
group by Email
having count(Email) > 1

官方代码

select Email from
(
  select Email, count(Email) as num
  from Person
  group by Email
) as statistic
where num > 1
;

# 作者：LeetCode

重新熟悉了group by 和having