PHP代码的纠结

<?php
require_once('conn.php');

$sql = " select * from studentInfo where id = '$_POST[account]' and  
												password = '$_POST[password]' ";
	
$re = mysql_query($sql);
$res = mysql_query($sql);
if(is_array(mysql_fetch_row($re)))
{
	$response[] = array("success" => "1");	
	$response[] = mysql_fetch_assoc($res);
}
//else
//{
 //	$response[] = array("success" => "0");
 	
 //}
 echo json_encode($response);
 mysql_close();
?>