Merging 2 tables from different databases using MERGE INTO

Question

I would like to use MERGE to merge 2 tables from different databases into one table. Both Databases are on the same server.

Currently, I can do the following:

USE Northwind2

SELECT a.CategoryID 
FROM Northwind.dbo.Categories a 
INNER JOIN Northwind2.dbo.Categories b ON a.CategoryID = b.CategoryID

However, I need to merge the results into one table. I thought I could do something like this:

USE Northwind2

MERGE INTO Categories B
USING (
  SELECT E.CategoryID
  FROM Northwind.dbo.Categories) E
ON (B.CategoryID = E.CategoryID)
WHEN MATCHED THEN
  //update the table
WHEN NOT MATCHED THEN
  //insert into the table

This will return an error saying the following:

Msg 10739, Level 15, State 1, Line 10
The insert column list used in the MERGE statement cannot contain multi-part identifiers. Use single part identifiers instead.

I'm not sure how I would remove the multi-part identifiers and still have this work... since I need to define which database we are looking in.

Any ideas on how I would get around this? Any help would be appreciated

Answer 1

This works for me:

MERGE INTO db1.dbo.TempCat B
USING (
  SELECT CategoryID
  FROM db2.dbo.TempCat) E
ON (B.CategoryID = E.CategoryID)
WHEN MATCHED THEN
  UPDATE SET CategoryID = E.CategoryID
WHEN NOT MATCHED THEN
  INSERT (CategoryID) VALUES (E.CategoryID);

I think the problem was the extra E. after SELECT -- you're defining E, so you can't use it there. No multi-part identifier needed.