[MSSQL] JOIN정리 LEFT JOIN, INNER JOIN, RIGHT JOIN 정리

--LEFT JOIUN
SELECT *
FROM TABLE A
LEFT JOIN TABLE B
ON A.ID = B.ID
WHERE B.KEY IS NULL

--;EFT JOIN
SELECT * 
FROM, TABLE A
LEFT JOIN TABLE B
ON A.ID = B.ID

--INNER JOIN
SELECT *
FROM TABLE A
INNER JOIN TABLE B
ON A. KEY = B.KEY

--RIGHT JOIN
SELECT *
FROM TABLE A
RIGHT JOIN TABLE B
ON A.KEY = B.KEY
WHERE A.KEY IS NULL

--RIGHT JOIN
SELECT *
FROM TABLE A
RIGHT JOIN TABLE B
ON A.KEY = B.KEY


--FULL OUTER JOIN
SELECT *
FROM TABLE A
FULL OUTER JOIN TABLE B
ON A.KEY = B.KEY

MSSQL을 공부하면서 필요한 JOIN의 명령어들을 정리합니다.

 

아래의 사이트를 접속하면 화면에서 더 쉽게 볼 수 있습니다.

https://sql-joins.leopard.in.ua/

SQL Joins Visualizer

 

1) LEFT JOIN

SELECT * FROM TableA A
LEFT JOIN TableB B ON
A.key = B.key WHERE B.key IS NULL

 

SELECT * FROM TableA A
LEFT JOIN TableB B ON
A.key = B.key

 

2) INNER JOIN

SELECT * FROM TableA A
INNER JOIN TableB B ON
A.key = B.key

 

 

3) RIGHT JOIN

SELECT * FROM TableA A
RIGHT JOIN TableB B ON
A.key = B.key WHERE A.key IS NULL

SELECT * FROM TableA A
RIGHT JOIN TableB B ON
A.key = B.key

 

 

4) FULL OUTER JOIN

SELECT * FROM TableA A
FULL OUTER JOIN TableB B ON
A.key = B.key