if (@string is null) set @string ='' select tblTasTests.id, tblItems.title as 'Name', tblItems.description as 'Beschreibung', tblMandators.name as 'Mandant' from tblTasTests inner join tblMandators on tblMandators.id=tblTasTests.mandator_id INNER JOIN tblItems ON tblItems.id = tblTasTests.id where (@mandator_id is null) or (tblTasTests.mandator_id=@mandator_id) and COALESCE(tblItems.titleForLearners, tblItems.title) like '%'+@string+'%' order by Name, Mandant