SQLD · 모의고사 12회 · 24번

MERGE INTO STOCK_T T
USING STOCK_S S ON (T.ITEM_ID = S.ITEM_ID)
WHEN MATCHED THEN
  UPDATE SET T.QTY = S.QTY
  DELETE WHERE (T.QTY = 0)
WHEN NOT MATCHED THEN
  INSERT (ITEM_ID, QTY) VALUES (S.ITEM_ID, S.QTY);