My database structure is like
Id Price Code
1 0.12 93
2 0.13 93
3 0.54 93
4 0.96 93
5 0.10 94
6
It can be done by some tricks.
SELECT id,
price,
code
FROM table1
WHERE id IN (SELECT Ceil(Avg(id)) AS `id`
FROM table1
GROUP BY code);
SQLFiddle
SELECT table1.*
FROM table1
JOIN (
SELECT SUBSTRING_INDEX(SUBSTRING_INDEX( GROUP_CONCAT(id ORDER BY id ASC), ',', CEIL(COUNT(*) / 2) ), ',', -1) AS id
FROM table1
GROUP BY CODE
) t USING(id)
http://sqlfiddle.com/#!2/fdc22/14