用一张表回更新另一张表
用一张表来更新另一张表
经典语句：UPDATE TABLE1 SET (A, B, C) = (SELECT A, B, C FROM TABLE2)
ORACLE：可以用MERGE语句(oracle 10g或以上),它是update和insert的组合.
MERGE INTO TABLE1 A
USING TABLE2 B
ON (A.OBJECT_ID = B.OBJECT_ID)
WHEN MATCHED THEN
UPDATE SET A.STATUS = B.STATUS
WHEN NOT MATCHED THEN
INSERT (OBJECT_ID, STATUS) VALUES (B.OBJECT_ID, B.STATUS)