SQL Server Matching on NULL parameter

So I have this query where I am trying to select on customer, unless the user doesn't enter a parameter for customer.  When they leave it blank, we want to see all customers.



So normally I would do it like this:




Select * from Orders where Customer=@customer
And then to handle the null parameter I would change it like this:




Select * from Orders where ((Customer = @customer) OR (@customer is null))
 This works great but then I came across this way of making it simpler.




Select * from Orders where Customer = isnull(@customer, Customer)
The isnull()  effectively handles the case where the parameter (@customer) is null by replacing it with the content of the [Customer] data column, matching to itself!  Problem solved!





...

---

Bryan Valencia is a contributing editor and founder of Visual Studio Journey.  He owns and operates Software Services, a web design and hosting company in Manteca, California.