CASE not working properly in SQL Server stored procedure

Question

I'm having an issue with using the CASE statement to change my ORDER BY statement in a stored procedure.

I'm sending in a parameter, @sortBy, which contains the name of the column to order by.

My issue is that the CASE statement works for most of the columns, but not others:

SELECT * FROM TapeView
                ORDER BY
                    CASE
                        WHEN @sortBy = 'BackupJobType' THEN [BackupJobType]
                        WHEN @sortBy = 'ItemID' THEN [ItemID]
                        WHEN @sortBy = 'MediaType' THEN [MediaType]
                        WHEN @sortBy = 'Category' THEN [Category]
                        WHEN @sortBy = 'Description' THEN [Description]
                        WHEN @sortBy = 'PlantName' THEN [PlantName]
                        WHEN @sortBy = 'BackupType' THEN [BackupType]
                        WHEN @sortBy = 'UserID' THEN [UserID]
                    END

For some reason, this works fine for every column except for BackupJobType and Description.

I have checked the value of the parameter being sent in and the names of the columns, and am 100% certain that they are correct.

I have a nearly-identical query on another page and both of these columns are working fine there.

Any ideas?

Edit: I forgot to mention that all of these columns are varchar datatypes

Answer 1

If the datatype of the @sortBy stored procedure parameter or local variable is anything smaller than the length of "Description", i.e. varchar(11), then that is your problem. For example, if @sortBy is varchar(10), then "Description" becomes "Descriptio" (first 10 chars) and "BackupJobType" becomes "BackupJobT", but the other column names fit. If this is the case, change the @sortBy data type of the procedure parameter and/or local variable to varchar(128).

Answer 2

The problem is probably caused by types. I would expect the ids to be a problem too, if they are numeric.

Putting each condition in a separate clause should fix the problem:

ORDER BY (CASE WHEN @sortBy = 'BackupJobType' THEN [BackupJobType] END),
         (CASE WHEN @sortBy = 'ItemID' THEN [ItemID] END),
         (CASE WHEN @sortBy = 'MediaType' THEN [MediaType] END),
         (CASE WHEN @sortBy = 'Category' THEN [Category] END),
         (CASE WHEN @sortBy = 'Description' THEN [Description] END),
         (CASE WHEN @sortBy = 'PlantName' THEN [PlantName] END),
         (CASE WHEN @sortBy = 'BackupType' THEN [BackupType] END),
         (CASE WHEN @sortBy = 'UserID' THEN [UserID] END)

The clauses that don't match will all product NULLs, so they will not affect the ordering.