Question

I have written following stored procedure. If I don’t use IF ELSE block Order by clause works fine but I need to use IF ELSE to build my select statement. Order by Is not working with IF else block. Can you please tell me what am I doing wrong?
Thanks in Advance!

ALTER PROCEDURE [dbo].[GetLookupItem] 

-- #description Gets LookupItem 
-- #tables   Subscriber.Reference.LookupItem,Subscriber.Reference.LookupText,Subscriber.Reference.LookupType
-- #parameter:   @LookupTypeId       This parameter defines a type of lookup
-- #parameter:   @LookupTextAbbreviationId            This Variable decides to tie Lookup Text to Abbreviation or Full Text. Most of the cases Full text will be used.
-- #parameter:   @LanguageCode     To show the Lookup Text in this Language

 @LookupTypeId int,
 @LookupTextAbbreviationId int ,
 @LanguageCode varchar(5)


AS

BEGIN

 SET NOCOUNT ON;
 DECLARE @MonthType int
 SET @MonthType = (SELECT Id FROM Subscriber.Reference.LookupType WHERE Name = 'Months')

 IF  @LookupTextAbbreviationId IS NULL
  BEGIN
   SELECT RLI.Id,RLT.Value
   FROM Subscriber.Reference.LookupItem RLI
   INNER JOIN Subscriber.Reference.LookupText RLT
   ON RLI.LookupTextId = RLT.Id AND RLT.LanguageCode = @LanguageCode AND RLI.LookupTextAbbreviationId IS NULL   -- LookupTextAbbreviationId will be null for full text records in Subscriber.Reference.LookupItem
   WHERE RLI.LookupTypeId = @LookupTypeId 
  END
 ELSE

  SELECT RLI.Id,RLT.Value
  FROM Subscriber.Reference.LookupItem RLI
  INNER JOIN Subscriber.Reference.LookupText RLT
  ON RLI.LookupTextAbbreviationId = RLT.Id AND RLT.LanguageCode = @LanguageCode
  WHERE RLI.LookupTypeId = @LookupTypeId


        ORDER BY                -- Order by will change for only Months by ID
        CASE  @LookupTypeId 
   WHEN @MonthType THEN RLT.Id 
   END,
  CASE 
   WHEN @LookupTypeId <> @MonthType THEN RLT.Value 
  END

 IF (@@ERROR <> 0)
  RETURN 1
 ELSE
  RETURN 0  

END

Answer 1

Do you want to order by RLT.Id when @LookupTypeId equals @MonthType and by RLT.Value otherwise? Then the case should be like this:

ORDER BY
CASE @LookupTypeId 
   WHEN @MonthType THEN RLT.Id
   ELSE RLT.Value
END

However, if RLT.Id and RLT.Value are not both the same type you will get a conversion error. If RLT.Id is int and RLT.Value is varchar then you could change the case to:

ORDER BY
CASE @LookupTypeId 
   WHEN @MonthType THEN STR(RLT.Id)
   ELSE RLT.Value
END