02. Create a function that returns the shipment date of a particular order.

create Function sales.calshipdate(@SalesOrderID int)Returns date
as
begin
Declare @shipDate Datetime
select @Shipdate=shipdate
from sales.salesOrderHeader
Where salesOrderID=@salesOrderID
If (@shipdate is Null)
set @shipdate=0
Return @shipdate
end


select salesOrderID,Sales.calshipdate(salesOrderID)
as Shipdate
from Sales.SalesOrderHeader