好烦啊，让我作android，2年没作过了，难受182. Duplicate Emails

两个sql  having效率高，比我本身写的快30ms，答案更简洁，我的习惯

我写的：

select a.Email from (select Email,count(Email) as num from Person group by Email) as a where a.num > 1

 

答案：

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

 

我以为答案更好，哈哈，不多用having，之后多用用，