NULL-betingelser i SQL Server

Du skal sende værdien af ​​Combobox i @Status :

Her skal du indstille betingelser som denne:

DECLARE @Status varchar(15)
--set the Status

SELECT * 
FROM tbl_Location
WHERE (@Status = 'All' 
       OR (@Status = 'Nulls' AND YEAR IS NULL) 
       OR (@Status = 'Not Nulls' AND YEAR IS NOT NULL)
      )