Question

I am trying to update a table from another database using joins and having a hard time. This is what I am trying to do in pseudo:

UPDATE [Database1].[dbo].[Sessions]
   SET [SpeakerID] = ?STATEMENT1?
 WHERE ?STATEMENT2?

For “Statement1”, this would be coming from another database and table that has columns: SessionID and SpeakerID. How can this be achieved?

Answer 1

UPDATE  a
SET     a.SpeakerID = b.colName          -- SET valoue here
FROM    Database1.dbo.Sessions a
        INNER JOIN Database2.dbo.Sessions b
            ON a.SessionID = b.SessionID -- assumes that their 
                                         -- relationship column is SessionID, 
                                         -- change it in your original columnName
WHERE   ....

a and b are called alias. They are useful when you have longer source name.