SQL - Group by

• create view: 뷰 생성
• select * from table: 테이블에서 칼럼 선택
• as는 칼럼의 이름을 간소화
• group by: 그룹열1, 그룹열2

원문(origin)의 행(row)이 2개 이상인 값을 구하는 쿼리문

CREATE VIEW v1 AS
SELECT org, anal, COUNT(org) AS cnt1
FROM ref_log
GROUP BY org, anal

CREATE VIEW v2 AS
SELECT v1.org AS org, COUNT(v1.org) AS cnt2
FROM (SELECT org, anal, COUNT(org) as cnt FROM ref_log GROUP BY org, anal) as v1
GROUP BY v1.org
HAVING cnt2 > 1

SELECT v1.org, v1.anal, v1.cnt1
FROM v1, v2
WHERE v1.org == v2.org AND v2.cnt2 > 1;