Description:
------------
When querying a MSSQL database table, and using the "not in" syntax, PHP's mssql_query will also return rows with NULL in the field specified.



Reproduce code:
---------------
SQL Server 2000 or 2005

Table "test"
test_id (int)  test_name (vchar)    test_number (int)
1              Foo                  1
2              Bar                  2
3              <null>               3
4              Baz                  <null>

$sql = "select test_id from test where test_number not in (1,2)";
$res = mssql_query($sql);
while ($row = mssql_fetch_array($res)) {
?>
<?=$row['test_id'];?><br/>
<?
}


Expected result:
----------------
In PHP, either using FreeTDS on Linux or the MSSQL extension on Windows, the above returns:

3
4

In ASP/VBScript or using Query Analyzer on Windows the following is returned:

3

Windows' MSSQL driver apparently will not compare the "not in" values to a NULL field.  PHP, apparently, will.

This creates and inconsistency between the two platforms.