Online PHP editor | output for UnvCk

<?php function comment_retrieve($amount = 0, $username = null, $file = null) { if ($file) { if ($amount > 0) { $querystring_file = ' AND `fc_forfile`=\'' . $username . '\''; } else { $querystring_file = ' WHERE `fc_forfile`=\'' . $username . '\''; } } else { $querystring_file = ''; } if ($username) { $querystring_username = ' WHERE `fc_byuser`=\'' . $username . '\''; } else { $querystring_username = ''; } if ($amount > 0) { $querystring_amount = ' LIMIT ' . $amount; } else { $querystring_amount = ''; } // query $querystring = "SELECT * FROM file_comments" . $querystring_username . $querystring_file . $querystring_amount; return $querystring; } echo comment_retrieve(7,null,'HJFG');