42.查找重复的电子邮箱
/*编写一个 SQL 查询，查找 Person 表中所有重复的电子邮箱。*/
SELECT email AS Email
FROM Person
GROUP BY email
HAVING COUNT(email) > 1;
/*编写一个 SQL 查询，查找 Person 表中所有重复的电子邮箱。*/
SELECT email AS Email
FROM Person
GROUP BY email
HAVING COUNT(email) > 1;