SQLD · 제61회 · 34번

SELECT COL1 FROM TBL1
MINUS
SELECT COL2 FROM TBL2;

-- (가)
SELECT COL1
FROM TBL1
WHERE COL1 NOT IN (SELECT COL2 FROM TBL2 WHERE COL2 IS NOT NULL);

-- (나)
SELECT COL1
FROM TBL1
WHERE NOT EXISTS (SELECT 1 FROM TBL2 WHERE TBL1.COL1 = TBL2.COL2);

-- (다)
SELECT T1.COL1
FROM TBL1 T1 LEFT JOIN TBL2 T2
ON T1.COL1 = T2.COL2
WHERE T2.COL2 IS NULL;