Query against two tables in separate databases on the same server

Sounds like you mistyped something. You can query a table in another DB using the following method:

SELECT tn.ID, tn.NAMEFROM [Database Name].[Schema].[TableName] as tn

I purposely added a two word database name because you have to put square brackets around that for it to be recognized. Your Schema will most likely be dbo.

If you show us your query and give us the DB names I can provide a more complete answer.

UPDATE:

Are you sure you are spelling "Center" correctly? I noticed you spelled it "centre" in IIPCentre_UserObject which I think might be right for the UK (?) but you spelled it "center" for QUALITY_CENTER. I would assume it's spelled one way or the other in your environment.

You can easily do that by providing the FQN (Fully Qualified Name) to the SQL object (in this case your SQL table). The FQN syntax for a table is as such:

[database-name].[schema-name].[table-name]

Example:

SELECT a, b, c FROM Database1.Schema1.Table1UNION SELECT a, b, c FROM Database2.Schema2.Table2

Where Database1 is your first database and Database2 is your second.

It's possible/straightforward to select from different databases on the same server. You need to use a fully qualified name i.e.

SELECT * from database.schema.table 

For example

SELECT * FROM northwind.dbo.orders where id = @id