How do you ORDER BY a parameter?

Just wondering if I could solicit some feedback on a stored procedure I'm running and whether there's a more efficient way of handling the scenario (I'm pretty sure there will be!).

Basically I have a single SP that I call to return a list of records (Jobs) that may have one or more statuses and a sort order (I'm using RowNum for paging). At the moment I'm using WITH RECOMPILE because the variations on the statuses can change all the time (depending on user etc). There's also some filtering going on.

I'm using an IF statement to essentially run the same bit of code with the only change being the sort order.

I guess my questions are: Is there a better way of doing this (maybe different SP's for different statuses)? Am I overcomplicating things due to lack of knowledge (quite likely) Is the SP actually ok, but requires minor tweaks to reduce the number of lines?

I've pasted a portion of the SP below - the only difference to the full code is the additional IF statements for the different sort orders...

I'd appreciate any feedback.

Thanks in advance!

```
PROCEDURE [dbo].[sp_Jobs]

@PageNumber int,
@PageSize int,
@FilterExpression varchar(500),
@OrderBy varchar(50),
@CustomerID int,
@ShowNotSet bit,
@ShowPlaced bit,
@ShowProofed bit,
@ShowReProofed bit,
@ShowApproved bit,
@ShowOnTime bit,
@ShowLate bit,
@ShowProblem bit,
@ShowCompleted bit,
@ShowDispatched bit,
@ShowUnapproved bit,
@ShowClosed bit,
@ShowReturned bit,
@UserID int

WITH RECOMPILE

AS

--JobNumber DESC
if @OrderBy='JobNumberDESC'
BEGIN

WITH Keys AS (SELECT TOP (@PageNumber * @PageSize) ROW_NUMBER() OVER (ORDER BY JobNumber DESC) as rn,P1.jobNumber,P1.CustID,P1.DateIn,P1.DateDue,P1.DateOut,p1.client,p1.MasterJobStatusID,p1.MasterJobStatusTimestamp,p1.OwnerID

FROM
vw_Jobs_List P1 WITH (NOLOCK)

WHERE
(@CustomerID = 0 OR CustID = @CustomerID)
AND (@UserID = 0 OR OwnerID = @UserID)
AND ((@ShowNotSet = 1 AND MasterJobStatusID=1) OR (@ShowPlaced = 1 AND MasterJobStatusID=2)

The sorting can be taken care of with a CASE expression, something along the lines of:

ORDER BY
    CASE WHEN @SortDirection = 'A' THEN
        CASE 
           WHEN @SortBy = 'JobNumber' THEN JobNumber
           WHEN @SortBy = 'JobId' THEN JobId 
        END
    END ASC
    , CASE WHEN @SortDirection = 'D' THEN
        CASE 
           WHEN @SortBy = 'JobNumber' THEN JobNumber
           WHEN @SortBy = 'JobId' THEN JobId 
        END
    END DESC

You may want to reconsider the OR'd where conditions as they are likely to generate poor plans. One of the best articles I've read covering this (and the alternative approaches) is Dynamic Search Conditions in T-SQL

Edit: Looking again at your parameter list, the primary filters appear to be @CustomerId and @UserId. I'd suggest creating two procs, spJobs_SelectByCustomerId and spJobs_SelectByUserId, which filter by their respective parameters so you eliminate the '@Param = 0 or Column = @Param' conditions. I guess the next important param is @ShowCompleted (presuming that once a job is 'done', it isn't shown unless @ShowCompleted=1), which i'd consider including in indexes on the CustomerId and UserId.

Edit2: Funny how these questions sometimes tick over in the back of your mind! :) On indexing @ShowCompleted, this is one of the occasions where Using a Low-Selectivity BIT Column First Can Be the Best Strategy. Filtered indexes should also be considered.

StackExchange Database Administrators Q#4104, answer score: 18