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
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