AS 
SELECT AdabasFiles.FileID
,(CASE WHEN MFAdabasFiles.FileName IS NOT NULL THEN MFAdabasFiles.FileName
         ELSE CONVERT(varchar(16), AdabasFiles.FileNumber) END) as fName 
, (CASE WHEN MFAdabasDB.DBName IS  NOT NULL THEN MFAdabasDB.DBName
         ELSE CONVERT(varchar(16), AdabasDatabases.DBNumber) END ) as db
FROM  AdabasFiles INNER JOIN AdabasDatabases ON AdabasDatabases.AdabasDBID=AdabasFiles.AdabasDBID
 LEFT JOIN MFAdabasFiles ON MFAdabasFiles.FileNumber=AdabasFiles.FileNumber
 LEFT JOIN MFAdabasDB ON MFAdabasDB.DBNumber= AdabasDatabases.DBNumber
