Sum of values based on usergroupid, using two tables

[brownafroduck]

Thanks for the quick reply!

I feel like I'm doing this completely incorrectly. This query gives me an array? Or what? I'm a complete noob at this, so here is my feeble attempt. I used the SQL that you gave me...

PHP Code:

$result= mysql_query("
                SELECT usergroupid, SUM(userfield16) AS total FROM " . TABLE_PREFIX . "user
                LEFT JOIN " . TABLE_PREFIX . "userfield USING (userid)
                GROUP BY usergroupid
                ") or die(mysql_error());
                
$points = mysql_fetch_array($result);

$group1= $points[0];
$group2= $points[1];
$group3= $points[2];
$group4= $points[3]; 


But I get this error...

Unknown column 'userfield16' in 'field list'

What am I doing wrong? What do I need to change? If I know that the usergroupid values that I need to sum up the points are 11, 12, 13, and 14, does that make it any easier? Is there perhaps some other approach that I can take to this with that knowledge?

Thanks!