add all values of a column in a query

[ukweb]

Hi there.

I am developing a php based program to invoice people, I got a really basic one for you here but I can't for the life of me remember how I did it last time!.

The query selects all outstanding records from an invoice table for a specific user. One of the columns is 'cost'. I want to add all the values of the 'cost' column from the results in the query. How do I do this? many thanks

Stephen

[Round]

try
$sql = "select sum(cost) as total from invoices where record =\"$oustanding\" and user = \"$user\" ";
$num= mysql_num_rows ($rs);
if ($num !=0)
{
$row = mysql_fetch_array( $rs );
$total = row["total"];
}
else
{
$total = 0;
}

tweak to suit