How do I write a series of SQL Server SELECT statements that compare tables in two databases with variables for the db names?

I want to write something like this

declare @db1 nvarchar(100);
declare @db2 nvarchar(100);

select id from [@db1]..MyTable t1 INNER JOIN [@db2]..MyTable t2 on [t1].id=[t2].id

but clearly SQL Server doesn't like the database names in variables - how can I achieve what I am trying to do?

I'm on but I'd like it as generic as possible for versions:
Microsoft SQL Server 2012 - 11.0.5058.0 (X64)
      May 14 2014 18:34:29
      Copyright (c) Microsoft Corporation
      Standard Edition (64-bit) on Windows NT 6.3 <X64> (Build 9600: )
purplesoupAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Vikas GargBusiness Intelligence DeveloperCommented:
Hi,

You can do something like this
declare @db1 nvarchar(100) = 'KPIFStaging'
declare @db2 nvarchar(100) = 'WintimeStaging'
DECLARE @SQL NVARCHAR(500)


SET @SQL = 'SELECT * FROM ' + @db1 + '.[dbo].[TransactionAudit]'

--PRINT @SQL -- To check the SQL

EXECUTE(@SQL)

Open in new window

0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Guy Hengel [angelIII / a3]Billing EngineerCommented:
I concur you cannot do without going dynamic sql  ( or going ad-hoc sql from outside the sql as such)
you cannot use variables for any of the following : database, table, column names etc ...
0
purplesoupAuthor Commented:
Ok thanks - when I saw the answer I guessed there wasn't going to be some more useful way to do it. I'm supplying a script to someone and it would have been useful for them to just set the names of the databases at the top of the script, but I think I'm just going to tell them to do a find and replace on the database names, going the dynamic sql route is going to ruin readability.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Microsoft SQL Server 2008

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.