SQLD · 모의고사 12회 · 22번

-- ㄱ
SELECT COUNT(*) FROM DATA_A, DATA_B;

-- ㄴ
SELECT COUNT(*) FROM DATA_A A INNER JOIN DATA_B B ON A.ID = B.ID;

-- ㄷ
SELECT COUNT(*) FROM DATA_A A FULL OUTER JOIN DATA_B B ON A.ID = B.ID;