MS Sql: Conditional ORDER BY ASC/DESC Question

I want to to make to make the ordering in my query conditional so if it satisfiess the condition it should be ordered by descending

For instance:

SELECT * FROM Data ORDER BY SortOrder CASE WHEN @Direction = 1 THEN DESC END

From stackoverflow

• I have done something like this

  select productId, InventoryCount, 
      case 
      when @Direction = 1 then InventoryCount 
      else -InventoryCount 
      end as "SortOrder"
  order by 3
  

  Shimmy : I don't understand what you wrote, anyway, I edited my query in the question please review the query.

  MikeW : My answer is essentially the same as the accepted answer, except his is better, having the logic entirely in the ORDER BY clause, where I've included a dummy column and ordered on that.

• Don't change the ASC or DESC, change the sign of the thing being sorted-by:

  SELECT * FROM table 
  ORDER BY 
  CASE WHEN @Direction = 1 THEN -id else id END asc;
  

  The OP asks:

  Guys, I am not the SQL Expert, please explain me what means the id and -id, does it controls the ordering direction?

  id is just whatever column you're sorting by; -id is just the negation of that, id * -1. If you're sorting by more than one column, you'll need to negate each column:

  SELECT * FROM table 
  ORDER BY 
  CASE WHEN @Direction = 1 THEN -id else id END 
  CASE WHEN @Direction = 1 THEN -othercolumn else othercolumn END ;
  

  If you're ordering by a non numeric column, you'll need to find an expression that makes that column "negative"; writing a function to do that may help.

  Shimmy : Guys, I am not the SQL Expert, please explain me what means the id and -id, does it controls the ordering direction?

  Shimmy : Also, I have edited my query, please review it.

  Shimmy : So I actually don't have to write ASC, Right?

  tpdi : Right, asc is the default.

• SELECT * 
  FROM Data 
  ORDER BY 
  Case WHEN @Direction = 1 THEN SortOrder END DESC, 
  Case WHEN 1=1 THEN SortOrder END