select *
from (
select if(@date = a.create_time, @rownum := @rownum + 1, @rownum :=1) as rownum,
@date:=a.create_time, a.column1, b.column2.....
from (
select *
from table
order by create_time, 数量 desc) a,
(select @rownum := 0, @date := '') b
) a
where a.rownum <= 10;