Puede ordenar por position, rand()
para tener un orden aleatorio dentro de cada position
dividir. Luego use variable para enumerar registros de position
particiones:
SELECT q_id, position, qtn, level, rn
FROM (
SELECT q_id, position, qtn, level,
@rn := IF(@pos = position, @rn + 1,
IF(@pos := position, 1, 1)) AS rn
FROM (
SELECT *
FROM tbl_question
WHERE level = '1'
ORDER BY position, rand() ) a
CROSS JOIN (SELECT @rn := 0, @pos := 0) AS vars ) b
WHERE b.rn <= 2
ORDER BY position
La consulta externa usa @rn
para seleccionar solo dos registros de cada position
partición.