Notice : Undefined variable when concatenating

Question

I have been making a script to display users and make changes to their admin privileges.

Here is the code:

    while ($row= mysql_fetch_assoc($query)         


        

Answer 1

Just set the variable to an empty string before you use it. You can't use .= on a variable that does not exist yet:

$insert = "";
while($row= mysql_fetch_assoc($query)) {
    // ...
    $insert .= '<tr>';
    // ...