[ INNER JOIN OUTER JOIN ] 이너조인 아웃터 조인 간단한 사용법

select A.COUNT_ID , A.MAKEDATE , A.MEMBER_ID FROM
( SELECT MEMBER_ID , COUNT(MEMBER_ID) AS COUNT_ID , CONVERT(VARCHAR(10), MAKEDATE ) AS MAKEDATE
FROM community_renew GROUP BY MEMBER_ID , CONVERT(VARCHAR(10), MAKEDATE )
) A
LEFT OUTER JOIN
(SELECT MEMBER_ID , COUNT( MEMBER_ID )AS COUNT_ID , CONVERT(VARCHAR(10), MAKEDATE ) AS MAKEDATE
FROM community_renew GROUP BY MEMBER_ID , CONVERT(VARCHAR(10), MAKEDATE )
) B
ON A.MEMBER_ID = B.MEMBER_ID AND A.MAKEDATE = B.MAKEDATE

간단한 예제

방문자수 대비 가입자수(OUTER JOIN)

그룹바이를 위해서 하위쿼리를 사용했습니다 꼭있는 자료에게LFET 를 위로 없을수 있는 자료를 오른쪽에다가 하세요
ISNULL(a.pageView , 0 ) <-- 값이 Null 일때 0으로 표시입니다
*/

--//실제 가입한 회원수
select ISNULL(a.pageView , 0 ) as pageView , b.makedate , b.with_member , b.entry_member from
(
select count(with_member) as entry_member , convert(varchar(10) , makedate ) as makedate , with_member from with_entry_member

group by convert(varchar(10) , makedate ) , with_member

)b --//a로 별칭 주다..

--//페이지 뷰
left outer join
(
select count(with_member_id) as pageView , convert(varchar(10) , makedate ) as makedate , with_member_id from FETISH_WITH_CONNECT
group by convert(varchar(10) , makedate ) , with_member_id

) a
on a.with_member_id = b.with_member

(INNER JOIN)

TALBE 두개의 값을 동시에 가지고 올때 사용합니다
SELECT * FROM REVIEW
INNER JOIN PRODUCT
ON

REVIEW.product_num =PRODUCT.product_num

SELECT REVIEW.product_num , COUNT(REVIEW.product_num) ,PRODUCT.product_name FROM REVIEW
INNER JOIN PRODUCT
ON
REVIEW.product_num =PRODUCT.product_num
GROUP BY REVIEW.product_num , PRODUCT.product_name