SQL Server : Null values do not match other null values.

http://msdn.microsoft.com/en-us/library/aa258291(v=sql.80).aspx



Note that NULL = NULL is NOT TRUE Also NULL <> NULL is NOT TRUE


INNER JOIN DOES NOT CONTAI N NULL VALUES IN OUTPUT


if ( NULL = NULL ) print 'yes' else
 print 'no'

output
-----------
no

 if ( NULL <> NULL ) print 'yes' else
print 'no'


output
-----------
no