use northwind
go
create procedure spMyOrders
@CustomerId char(5) = null,
@employeeId int = null
as
select 	* 
from 	orders
where	(CustomerId = @CustomerId or @CustomerId is null) and
	(employeeId = @employeeId or @employeeId is null)
go

exec spMyOrders null, null -- all data
exec spMyOrders 'VINET', null -- all data that have 'VINET' for customerId
exec spMyOrders null, 6 -- all data that have 6 for employeeId
exec spMyOrders 'VINET', 6 -- all data that have 'VINET' for customerId and  6 for employeeId

go

drop procedure spMyOrders