Genom att använda denna teknik .
select sch_code,
schabbrev,
ROUND( AVG( totpct_stu ), 1 ) AS top10
from (select sch_code,
schabbrev,
totpct_stu,
@num := if(@group = sch_code, @num + 1, 1) as row_number,
@group := sch_code as dummy
from test_table
order by sch_code, totpct_stu desc) as x
where row_number <= 10
GROUP BY sch_code,
schabbrev