[LeetCode] 182. Duplicate Emails (Oracle)

LeetCode - Problems - Database - 182. Duplicate Emails

Given SQL Schema

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')

Problem Description

Write a SQL query to find all duplicate emails in a table named Person.

For example, your query should return the following for the above table:

Note: All emails are in lowercase.

My Solution (Oracle)

SELECT email
FROM person
GROUP BY email
HAVING COUNT(email) > 1;

간단하게 HAVING 절을 이용했다.

COUNT 함수를 통해 같은 email이 1개 초과인 경우, 해당 이메일을 선택한다.