Microsoft SQL Server NULLs


In SQL Server, NULL represents data that is missing, or unknown. This means that NULL is not really a value; it's better described as a placeholder for a value. This is also the reason why you can't compare NULL with any value, and not even with another NULL.


SQL Server provides other methods to handle nulls, such as IS NULL, IS NOT NULL, ISNULL(), COALESCE() and others.