最大值 最小值 最初值 最末值

//最大最小价
select max(price) max,min(price) min,time time from on_jiaoyi_into 
group by DATE_FORMAT(`time`,'%Y-%m-%d') 

//最初价
select price,time from on_jiaoyi_into  group by DATE_FORMAT(`time`,'%Y-%m-%d')  order by time   

//最末价
select price,time from on_jiaoyi_into  group by DATE_FORMAT(`time`,'%Y-%m-%d')  order by time desc