Ambiguous column when update with remote server in SQL server? - sql-server

Question

I have 2 SQL servers .
dstest\mssql2008 <--I'm currently at this instance ( server)
dstrn <-- another server
Both servers has the same table called :
EServices_Pages_Content
Goal : I need to update data on dstest from dstrn
On the current server (dstest) I have :
I can(!) access dstrn from dstest :
SELECT * FROM dstrn.weberp.dbo.EServices_Pages_Content WHERE pageid=80
OKay.
So where is the problem ?
As I told , I need to update data on dstest(current db) from a far server (dstrn) so I do :
UPDATE EServices_Pages_Content
SET [Content] = a.Content
FROM [dstrn].weberp.dbo.EServices_Pages_Content a
WHERE PageID = a.pageID
AND MasterEntityID = a.masterEntityid
AND LanguageID = a.LanguageID
AND PageID = 80
But I get an error :
Msg 209, Level 16, State 1, Line 4
Ambiguous column name 'PageID'.
Msg 209, Level 16, State 1, Line 5
Ambiguous column name 'MasterEntityID'.
Msg 209, Level 16, State 1, Line 6
Ambiguous column name 'LanguageID'.
Msg 209, Level 16, State 1, Line 7
Ambiguous column name 'PageID'.
I don't understand , I did use aliases , why does it tell me Ambiguous columns? How can I fix it ?
Edit : I found a way to make it work( see my answer) - but still can't understand why I need full table prefix in the where clause. - and can't use aliases to prevent Ambiguity

Answer 1

Try this:
UPDATE Dest
SET [Content] = a.Content
FROM EServices_Pages_Content Dest
INNER JOIN [dstrn].weberp.dbo.EServices_Pages_Content a
ON Dest.PageID = a.pageID
AND Dest.MasterEntityID = a.masterEntityid
AND Dest.LanguageID = a.LanguageID
WHERE a.PageID = 80
Explanation:
Using an alias on just one of the tables is not enough.
Since both of the tables have the same names and the same column names,
you need to specify an alias to the destination table as well, and use a multi-part name for it's columns.
Also, you are using an implicit join. Since explicit joins more readable, I would recommend to never use implicit joins.

Answer 2

I have created 2 test tables ( on the same server) :
Table testA
Table testB
Now , for simplicity - let's say I want to update tableA from tableB but only only for pageId=2 :
So first I tried :
UPDATE testA a
SET a.[Content] = b.Content
FROM testB b
WHERE a.PageID = b.pageID
AND a.PageID = 2
But I got an error :
Msg 102, Level 15, State 1, Line 6
Incorrect syntax near 'a'.
So then I tried :
UPDATE testA
SET [Content] = b.Content
FROM testB b
WHERE testA.PageID = b.pageID -- notice prefix
AND testA.PageID = 2 -- notice prefix
And Then :
(1 row(s) affected)
And now you can see it's ok :

Answer 3

You need some join here:
UPDATE d
SET [Content] = a.Content
FROM EServices_Pages_Content d
JOIN [dstrn].weberp.dbo.EServices_Pages_Content s ON d.PageID = s.pageID
AND d.MasterEntityID = s.masterEntityid
AND d.LanguageID = s.LanguageID
AND d.PageID = 80