DB 6일차 1(서브쿼리)

많이 쓰지 마라.

select * from user_mst;
select * from user_dtl;

 

SELECT 
	*
FROM
	user_dtl
 where
	id = (select id from user_mst where username = 'test');
    
    /*user_mst에서 username이 test 인 것을 찾겠다.*/

 

select
	*
from
	user_dtl
where
	id in (select id from user_mst where username like '%test%'); 
    /* test 가 포함되고 있는거*/
    /* in 은 포함관계*/

 

select 
	*
from
	user_dtl ud
    left outer join user_mst um on(um.id = ud.id)
where
	um.username = 'test';