As a SQL Server developer, it is important to optimize the performance of your queries and stored procedures. One common performance issue is when a stored procedure needs to dynamically build a SQL string for the ORDER BY clause. This can lead to poor performance as the stored procedure has to recompile every time due to the use of EXEC or sp_executesql.

In this article, we will discuss a solution to improve performance and remove the logic of preparing the ORDER BY clause from the application. The solution involves using multiple CASE statements.

Let’s consider an example using the AdventureWorks sample database. Suppose we have a stored procedure that takes two input parameters: @OrderBy and @OrderByDirection. These parameters determine the column to be sorted and the sort direction, respectively.

Here is the modified query:

USE AdventureWorks

DECLARE @OrderBy VARCHAR(10)
DECLARE @OrderByDirection VARCHAR(1)

SET @OrderBy = 'State' -- Other options: Postal for PostalCode, City for City
SET @OrderByDirection = 'D' -- Other options: A for ascending, D for descending

SELECT AddressID, City, StateProvinceID, PostalCode
FROM person.address
WHERE AddressID < 100
ORDER BY
    CASE WHEN @OrderBy = 'Postal' AND @OrderByDirection = 'D' THEN PostalCode END DESC,
    CASE WHEN @OrderBy = 'Postal' AND @OrderByDirection != 'D' THEN PostalCode END,
    CASE WHEN @OrderBy = 'State' AND @OrderByDirection = 'D' THEN StateProvinceID END DESC,
    CASE WHEN @OrderBy = 'State' AND @OrderByDirection != 'D' THEN StateProvinceID END,
    CASE WHEN @OrderBy = 'City' AND @OrderByDirection = 'D' THEN City END DESC,
    CASE WHEN @OrderBy = 'City' AND @OrderByDirection != 'D' THEN City END

In this query, we use multiple CASE statements to conditionally sort the result set based on the values of @OrderBy and @OrderByDirection. Each CASE statement checks the values of the parameters and returns the corresponding column to be sorted. The DESC keyword is used to specify the sort direction when @OrderByDirection is set to ‘D’.

This approach eliminates the need for dynamic SQL execution using EXEC or sp_executesql, resulting in improved performance. The stored procedure no longer needs to recompile every time it is executed.

By using multiple CASE statements, we can handle different sorting scenarios efficiently. The example query can be tested with different options for @OrderBy and @OrderByDirection to see the desired sorting behavior.

Implementing this logic in your own applications can help improve performance and simplify the code by removing the need for dynamic SQL execution. It is a best practice to minimize the use of dynamic SQL whenever possible.

Next time you encounter a similar scenario where you need to dynamically build the ORDER BY clause, consider using multiple CASE statements as a performance-enhancing solution.

Let me know if you have any questions or if you have implemented a similar logic using any other method.