i need to know how to get sum of field named $amount?
Please help..

below is some of the sql query:

$query = "select policynum, CONVERT(varchar(10), ar.addDate, 101) AS TransDAte,

Amount

from ar, policy

where DATEDIFF(day,ar.adddate,('$_POST[start_date]')) <= 0

and DATEDIFF(day,ar.adddate,('$_POST[end_date]')) >= 0

and ar.policyid = policy.policyid

and artype = 25

order by policynum


";


//execute the SQL statement and return records
$rs = $conn->execute($query);
$policynumber = $rs->Fields(0);
$transdate = $rs->Fields(1);
$amount = $rs->Fields(2);
$sumamount = $rs->Fields(3);