DB2中的SQL，用于连接多次更新

Question

我有一张这样的桌子...... Table Desc

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现在我的工作是复制EMAIL_ADDRESS，其中两个或多个记录的EMAIL_ADDRESS_ENCRYPT相同。 任何人都可以帮助SQL ... 我试过这个

UPDATE
    Table_A
SET
    Table_A.email_address = Table_B.email_address
FROM
    MEMBER_EMAIL AS Table_A
    INNER MEMBER_EMAIL AS Table_B
        ON Table_A.member_id = Table_B.member_id

但这不适用于DB2。

提前致谢

Answer 1

我认为DB2不支持更新中的cellForRowAtIndexPath（与T-SQL相同）。你可以这样做：

FROM

Answer 2

虽然是旧的，但问题中缺少一个条件，但

怎么样

MERGE INTO MEMBER_EMAIL TABLE_A
USING (
    SELECT TABLE_B.MEMBER_ID, TABLE_B.EMAIL_ADDRESS 
    FROM MEMBER_EMAIL TABLE_B --<i>you can add some WHERE here to (un)complicate things</i>
    ) AS TABLE_C
ON 
TABLE_A.MEMBER_ID = TABLE_C.MEMBER_ID
WHEN MATCHED THEN UPDATE SET
TABLE_A.EMAIL_ADDRESS = TABLE_C.EMAIL_ADDRESS
;