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.