SQL Server output parameter issue

Question

I am using SQL Server 2008 Enterprise. I am learning OUTPUT parameter of SQL Server stored procedure. For example, stored procedure sp_add_jobschedule has an OUTPUT paramete

Answer 1

Yes, you can use an OUTPUT parameter for both passing in and retrieving values (although I can't think of a good reason to do that at the moment).

Here's a trivial example that demonstrates this:

-- The stored procedure
CREATE PROCEDURE OutParamExample
    @pNum int OUTPUT
AS
BEGIN
    select @pNum
    set @pNum = @pNum + 5
END
GO

-- use a local variable to retrieve your output param value
declare @TheNumber int
set @TheNumber = 10

print @TheNumber
exec OutParamExample @TheNumber OUTPUT
print @TheNumber

The results will look like this:

10

-----------
10

(1 row(s) affected)

15

EDIT: OK, I think I missed a "not" in the second paragraph and may not have answered the question you asked. If you want a strict output parameter (e.g. something like a return code), you certainly don't have to provide a value to the local variable passed as the output parameter, but you still have to declare that local variable so that you'll have a way of accessing the returned value outside of the scope of the procedure itself.

For example:

declare @LocalNumber int
-- I don't have to assign a value to @LocalNumber to pass it as a parameter
exex OutParamExample @LocalNumber OUTPUT  
-- (assume SP has been altered to assign some reasonable value)

-- but I do have to declare it as a local variable so I can get to
-- the return value after the stored procedure has been called
print @LocalNumber