테이블
Person 테이블
| id | |
|---|---|
| 1 | a@b.com |
| 2 | c@d.com |
| 3 | a@b.com |
문제
- 중복되는 email만 뽑으시오
답
SELECT p.email AS email
FROM Person p
GROUP BY p.email
HAVING COUNT(*) > 1
;
스키마
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');