want to seprate values in while loop

[workwithphp]

hello i want to seprate values display by my while loop.The result is 200,900. i want to slpit as 200 and 900. i used the explode function but only return the value on exmple[1] index not on zero but i want to get the value '200' also is there any way i can do this please help me.
Thanks

$sql = mysql_query("SELECT `amount`,`id` FROM subhead_name  WHERE `id` ='2' OR '4'");

while($stuInfo = mysql_fetch_assoc($sql))
{
 $Data = $stuInfo['amount'].",";
    
}