SQL错误：多次指定表名

Question

I am getting the error Table name specified more than once after executing this code:

UPDATE Ref_zak_tab
SET uexdate = dbo.Data_inf.date
FROM dbo.Ref_zak_tab CROSS JOIN dbo.Data_inf

What can I do with this?

After trying alias I get this:

UPDATE Ref_zak_tab rzt
SET uexdate = dbo.Data_inf.date
FROM dbo.Ref_zak_tab CROSS JOIN dbo.Data_inf

Update cancelled: attempt to update a target row with values from multiple join rows

Answer 1

For each row in the Ref_zak_tab table CROSS JOIN with the Data_inf table returns multiple rows and perhaps therefore UPDATE operator can not be successfully executed.

Try to use INNER JOIN instead.

UPDATE rzt
SET rzt.uexdate = dt.date
FROM dbo.Ref_zak_tab rzt
INNER JOIN dbo.Data_inf dt ON (*join condition here*)

Answer 2

Are you trying to do what standard SQL would spell out as

SET uexdate = (SELECT date FROM dbo.Data_inf WHERE (condition here to determine single row in Data_inf) )

?

If so, then just write it like that.