Question:
I want to use Union to union two different tables, but they are in different databases. An error message told me that I can’t use Union in this way. How can I do that? Both tables use the same schema.
Answer:
You have to prefix the query with the database name to get access to the other database’s tables. If the schemas are identical, then they should union. Here’s a simple example of the prefix:
select au_id from pubs.dbo.authors UNIONselect customerid from northwind.dbo.invoices