반응형 sql join1 MySQL - group by, having, join 💡 group by 문 -- rental 테이블로부터 user_id별로 user_id를 조회한다. -- select user_id from rental group by user_id; -- user_id별로 개수 세기 -- select user_id, count(*) from rental group by user_id; 💡 having 조건문 select user_id, count(*) from rental group by user_id having count(user_id) > 1; select user_id, count(*) from rental group by user_id having count(user_id) < 1; select user_id, count(*) from rental group .. 2022. 7. 18. 이전 1 다음 728x90 반응형
