Question

I would like to create a stored proc that has an optional parameter in the WHERE part of the proc. My C# code can pass in null or a valid product id for this proc. Here it is:

declare @ProductID int
set @ProductID = null

select
    *
from
    Products
where   
    Name like '%Hasbro%'
    if @ProductID is not null
        begin
            and ProductID = @ProductID
        end

This code doesn’t work. If the product id is null, I want it to only look for products with the name ‘Hasbro’ in it. If the product id is not null, I want it to look for products with the name ‘Hasbro’ in it and for matching product ids.

Thanks!

UPDATE:

Here is the working code. Thank you everyone for helping me get this!

declare @ProductID int
set @ProductID = null

select
    *
from
    Products
where
    Name like '%Hasbro%'
    and (( @ProductID is null ) or ( @ProductID is not null and ProductID = @ProductID ))

Answer 1

This should work also…

select
    *
from
    Products
where
    Name like '%Hasbro%' and
    (
      ( @ProductID is null ) or
      ( @ProductID is not null and ProductID = @ProductID ) 
    )