Note - My answer below received a couple down votes, but only one comment giving any reason why it might be down-voted. The comment was that this answer is very similar to the accepted answer, but even less performant. I disagree with this opinion and I reproduce my response here - in the actual answer - so that anyone else reading my answer might have a better chance at seeing why this is not the same as the accepted answer at all, and in fact better addresses the original question.
My response to the suggestion this is similar to the accepted answer:
on the contrary - the original question notes that new databases are added regularly. The accepted solution will require maintenance each time a new database is added. The solution here will work regardless of whether any new databases are added (in line with the original question that states they all have the same schema). Further, the accepted answer requires you to duplicate the query once per database queried. If the query is complex, that gets ugly fast. The proposal here ensures a single source of truth for the logic being used in the query.
And the answer itself:
Shooting from the hip here.
use master;
go
create table #Temp (sourceDBName varchar(128), colA varchar(128), colB varchar(128));
exec sp_MSforeachDB ' USE [?];
insert into #Temp
SELECT DISTINCT
''?'',
tableA.colA,
tableB.colB
FROM tableA JOIN tableB on some_conditions
WHERE someCol LIKE ''%some_term%''
'
select sourceDBName, colA, colB from #Temp order by 1, 2, 3;
drop table #Temp;
This logic should allow you to apply a single query to all databases. To use it though, you will want to add logic to filter out system databases, or explicitly include only the databases you specify. To achieve that, you might like to put this logic into a stored procedure which then returns a result set, so in the end, your call to this logic is a select statement that returns a rowset you can join, filter, etc.
