Question

UPDATE tab4mail SET emid = 'X' WHERE
(

SELECT tab1.colum1, tab1.colum2, tab1.status, tab2.idnr, tab2.role, tab3.colum2, tab4mail.emid

FROM tab1 JOIN tab2 ON tab1.colum1 = tab2.column9

JOIN tab3 ON (tab1.colum1 = tab3.colum1 and tab1.colum2 = tab3.colum2)

JOIN tab4mail ON tab2.idnr = tab4mail.idnr

WHERE tab1.status = 'X' and tab2.role = 'S'

);

括号中的SELECT命令用于显示行。

现在我想更新表“tab2mail”并想要设置为“X”。我不知道在哪里写/添加此UPDATE。在第一行或其他地方？我只想在“tab4mail”中替换满足SELECT命令条件的这些行，用括号括起来。

Answer 1

我认为你想要一个相关的子查询：

UPDATE tab4mail
    SET emid = 'X'
    WHERE EXISTS (SELECT 1
                  FROM tab1 JOIN
                       tab2
                       ON tab1.colum1 = tab2.column9 JOIN
                       tab3
                       ON tab1.colum1 = tab3.colum1 and tab1.colum2 = tab3.colum2
                  WHERE tab2.idnr = tab4mail.idnr AND tab1.status = 'X' and tab2.role = 'S'
                 );

Answer 2

您想使用IN子句。

UPDATE tab4mail 
SET emid = 'X' 
WHERE idnr IN (
        SELECT tab4mail.idnr 
        FROM tab1 JOIN tab2 ON tab1.colum1 = tab2.column9
        JOIN tab3 ON (tab1.colum1 = tab3.colum1 and tab1.colum2 = tab3.colum2)
        JOIN tab4mail ON tab2.idnr = tab4mail.idnr
        WHERE tab1.status = 'X' and tab2.role = 'S'
    )

括号中的SELECT命令用于显示行，如何更新表？

2 个答案: