开盘价，收盘价，最高价，最低价的再次分析

//最大值
select max(price) max,date from on_jiaoyi_into group by date
//最小值
select min(price) min,date from on_jiaoyi_into group by date
//开盘价
select a.price,a.date from 
(
select price,date from on_jiaoyi_into where sid=3
order by date,time 
) a group by date
//收盘价
select a.price,a.date from 
(
select price,date from on_jiaoyi_into where sid=3
order by date,time desc
) a group by date












select zdz.max,zxz.min,kpj.kpj,spj.spj from 

(/*最大值*/select max(price) max,date,id from on_jiaoyi_into group by date) zdz 

left join 

(/*最小值*/select min(price) min,date,id from on_jiaoyi_into group by date) zxz 

on zdz.id=zxz.id

left join

(/*开盘价*/select a.price kpj,a.date,a.id from (select price,date,id from on_jiaoyi_into where sid=3 order by date,time ) a group by date ) kpj

on zdz.id=kpj.id

left join

(/*收盘价*/select b.price spj,b.date,b.id from (select price,date,id from on_jiaoyi_into where sid=3 order by date,time desc) b group by date ) spj 

on zdz.id=spj.id

最后join出来的结果有一个字段是空值，最后想了想，因为他们的最大值、最小值、开盘价、收盘价有可能不是一个ID。。。。。

那么，只有把上面四条语句查询出来的结果用合并数组的方法才是正确的。。。