join
INNER JOIN
교집합
INNER JOINLEFT JOIN or RIGHT JOIN
부분 집합
LEFT JOIN
RIGHT JOINOUTER JOIN
합집합
ex>
SELET A.ID, B.ID
FROM A RIGHT OUTER JOIN B
ON A.ID = B.ID
WHERE A.ID = 1;
한다. 간다. 해낸다.
교집합
INNER JOIN부분 집합
LEFT JOIN
RIGHT JOIN합집합
SELET A.ID, B.ID
FROM A RIGHT OUTER JOIN B
ON A.ID = B.ID
WHERE A.ID = 1;