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Oracle MERGE????????????????????????????????????????????????????????Oracle MERGE?????????????????????

1. MERGE???????

MERGE INTO?? USING??????ON????WHEN MATCHED THEN????WHEN NOT MATCHED THEN????

??MERGE????????USING???????????ON???????????WHEN??????????????????

2. ??DUAL??????

??????????????MERGE????DUAL??????????????????????????

MERGE INTO TEST T1USING (SELECT '2' AS ID, 'newtest2' AS NAME FROM DUAL) T2ON (T1.ID = T2.ID)WHEN MATCHED THEN    UPDATE SET T1.NAME = T2.NAMEWHEN NOT MATCHED THEN    INSERT (T1.ID, T1.NAME) VALUES (T2.ID, T2.NAME);

3. ??????

??????????TEST??????ID?VALUE??????????????

CREATE TABLE TEST (    ID INTEGER,    VALUE VARCHAR2(255));INSERT INTO TEST VALUES (1, 'test1');INSERT INTO TEST VALUES (2, 'test2');

?????????MERGE?????????????????ID=2??????NAME='newtest2'????MERGE??????

MERGE INTO TEST T1USING (SELECT '2' AS ID, 'newtest2' AS NAME FROM DUAL) T2ON (T1.ID = T2.ID)WHEN MATCHED THEN    UPDATE SET T1.NAME = T2.NAMEWHEN NOT MATCHED THEN    INSERT (T1.ID, T1.NAME) VALUES (T2.ID, T2.NAME);

4. MERGE???????

???????MERGE??????????????

• ???????????????????????
• ??????????????????????
• ?????????????????????

5. ????

• ???????ON??????????????????????
• ?????????WHEN?????????????????
• ??????MERGE??????????????????????????????????

??????Oracle MERGE????????????????????????????????

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