Could you provide a short example of a code that reproduces
this?

<?php
$db = mssql_connect("localhost", "xxx", "yyy");
mssql_select_db("zzz", $db);

$result = mssql_query("select NULL as test", $db);

mssql_fetch_row($result);
$blah = mssql_result($result, 0, "test");

$huh = NULL;


echo is_null($blah);		// false
var_dump($blah);		// bool(false)

echo is_null($huh);		// true
var_dump($huh);			// NULL
?>

This seems due to PHP assuming MySQL's return values are strings, which point it is converted into an empty sting. Probably your best bet is to test for a "". I think this behaviour is documented somewhere.

James

i think this is not an acceptable behaviour. "" could be everything, an empty string, an integer field with the value null or even a field set to NULL.
as you obviously noticed we are talking from database interfaces in general, not only mysql (as you can see we where talking about mssql in detail).

at least i would make this a feature request.