optional parameters in SQL Server stored proc?

问题:

I'm writing some stored procs in SQL Server 2008, and wondered if the concept of optional input parameters is possible here?

I suppose I could always pass in NULL for parameters I don't want to use, check the value in the stored proc, then take things from there, but I was interested if the concept is available here. Thanks!

回答1:

You can declare like this

CREATE PROCEDURE MyProcName
    @Parameter1 INT = 1,
    @Parameter2 VARCHAR (100) = 'StringValue',
    @Parameter3 VARCHAR (100) = NULL
AS

/* check for the NULL / default value (indicating nothing was passed */
if (@Parameter3 IS NULL)
BEGIN
    /* whatever code you desire for a missing parameter*/
    INSERT INTO ........
END

/* and use it in the query as so*/
SELECT *
FROM Table
WHERE Column = @Parameter

回答2:

Yes, it is. Declare parameter as so:

@Sort varchar(50) = NULL

Now you don't even have to pass the parameter in. It will default to NULL (or whatever you choose to default to).

回答3:

2014 and above at least you can set a default and it will take that and NOT error when you do not pass that parameter. Partial Example: the 3rd parameter is added as optional. exec of the actual procedure with only the first two parameters worked fine

exec getlist 47,1,0

create procedure getlist
   @convId int,
   @SortOrder int,
   @contestantsOnly bit = 0
as