PHP call to mysqli_query returns null (as expected) but I don't seem to be able to detect it

Jonathan Davies

My SELECT query works fine when I've got records. Whether there are no records, or not in the result set I get a warning

Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, null given

I've tested the result agains

FALSE, NULL, null

(both null and NULL seem to be used in examples and the manual)and calling

is_null($result)

but I don't pick it up. Why? I just want to be able to differ between technical failure and return of zero records.

$query = 'SELECT CommentId, ParentId, Subject, Name, DATE_FORMAT(TimeStamp,"%k::%i %d-%m-%Y (GMT)"), Comment FROM commentdata WHERE ArticleId = ' . $ArticleId . ' ORDER BY COALESCE ( ParentId, CommentId)';

    $result = mysqli\_query($connect, $query);
    
    if(TRUE == $result)
    {
        echo 'TRUE returned on query for data: ' . mysqli\_error($connect) . '

';
}

    if(FALSE == $result)
    {
        echo 'FALSE returned on query for data: ' . mysqli\_error($connect) . '

';
mysqli_close($connect);
die("Connection closed after FALSE returned on query for data: " . mysqli_error($connect));
}

    if(NULL == $result))
    {
        echo 'NULL returned on query for data: ' . mysqli\_error($connect) . '

';
mysqli_close($connect);
die("Connection closed after NULL returned on query for data: " . mysqli_error($connect));
}

    if(null == $result))
    {
        echo 'null returned on query for data: ' . mysqli\_error($connect) . '

';
mysqli_close($connect);
die("Connection closed after null returned on query for data: " . mysqli_error($connect));
}

    if(is\_null($result))
    {
        echo 'NULL returned on query for data: ' . mysqli\_error($connect) . '

';
mysqli_close($connect);
die("Connection closed after NULL returned on query for data: " . mysqli_error($connect));
}

    /\* determine number of rows in result set \*/
    $rowcount = mysqli\_num\_rows($result);