VERSCHIL berekenen tussen 2 queries met 1 query in een keer

[patrickphpsql]

$sql10 = "SELECT 02member.FIRSTNAME, 02member.SURNAME, Sum(IFNULL(POINTS,0)) as PLUS
FROM 02member LEFT JOIN 04exchange on 02member.IDLID = 04exchange.refDONOR
GROUP BY FIRSTNAME, SURNAME
ORDER BY FIRSTNAME, SURNAME";

Result : Charles Great : 2200

$sql11 = "SELECT 02member.FIRSTNAME, 02member.SURNAME, Sum(IFNULL(POINTS,0)) as MIN
FROM 02member LEFT JOIN 04exchange on 02member.IDLID = 04exchange.refRECEIVER
GROUP BY FIRSTNAME, SURNAME
ORDER BY FIRSTNAME, SURNAME";

Result : Charles Great : 1000

The goal is to get the difference between the 2, preferable along one query (subquery)

Charles Great : 2200 - Charles Great 1000 = Charles Great : 1200 = I need this result