How to select distinct with multi field

In the most common usage, select distinct using as select operator for only 1 field, for example:

SELECT DISTINCT memid
FROM common.members
WHERE memid > 3000;

But sometime, you need select associated field like username or password, or point, you need a query like this:

SELECT DISTINCT (memid), MAX(point2) AS point2max
FROM common.mempoint200812
WHERE clientid = 27
AND pointkind = 20
GROUP BY memid
ORDER BY point2max DESC ;