Friday, January 27, 2012

CLR Stored Proc with Output Value Returning NULL

I'm a little embarrassed to be writing a post about this but I figured there might be someone else out there making the same obvious mistake that might find this useful.

I recently created a CLR stored procedure that returns a value. Not a return code but an actual calculated output. To implement this in C# it is necessary to declare an output parameter in the method definition similar to the following.

public static void CLRSum(SqlInt32 val1, SqlInt32 val2, out SqlInt32 value)
   value = val1 + val2

As I alluded to in the title of this post, calls to my new CLR stored procedure where returning NULL. Below is how I was calling my CLR stored procedure from T-SQL.
EXECUTE dbo.CLRSum 4, 3, @value 

Notice anything missing? Took me a little while but I finally realized I was missing the output keyword. The correct way to call the stored proc is below.
EXECUTE dbo.CLRSum 4, 3, @value output


  1. Thank you... Thank you...Thank you...
    I can go home today, Friday evening knowing I have a clr proc that works ready for use in my project next week.

  2. OMG thank you! Couldn't figure out why my output parameter was always getting set to 0.

  3. Seven years later, and your post is still helping people. Thanks :)