Complex Database query--Help Please

I am tgrying to find the median value in a table.

This works:

Code:

SELECT round(AVG(middle_values),0) AS 'median' FROM (
 SELECT t1.masterpoints_total AS 'middle_values' FROM
   (
     SELECT @row:=@row+1 AS `row`, x.masterpoints_total
     FROM members AS x, (SELECT @row:=0) AS r
     WHERE 1
     -- put some where clause here
     ORDER BY x.masterpoints_total
   ) AS t1,
   (
     SELECT COUNT(*) AS 'count'
     FROM members x
     WHERE 1
     -- put same where clause here
   ) AS t2
   -- the following condition will return 1 record for odd number sets, or 2 records for even number sets.
   WHERE t1.row >= t2.count/2 AND t1.row <= ((t2.count/2) +1)) AS t3;

I am not sure how to write the query buidler.

Thanks.

Bill Hogsett