题目描述
编写一个 SQL 查询,查找 Person 表中所有重复的电子邮箱。
示例:
+—-+———+ | Id | Email | +—-+———+ | 1 | a@b.com | | 2 | c@d.com | | 3 | a@b.com | +—-+———+ 根据以上输入,你的查询应返回以下结果:
+———+ | Email | +———+ | a@b.com | +———+
Note:
解题思路
# Write your MySQL query statement below
select Email from
(
select Email, count(Email) as num
from Person
group by Email
) as statistic
where num > 1
;