把时间设置date类型，其中
select count(*),year(b.date),month(b.date) ,day(b.date) from person as b group by year(b.date),Month(b.date), day(b.date) order by b.date desc查询结果
select count(*),year(b.date),month(b.date) ,day(b.date) from person as b group by year(b.date),Month(b.date), day(b.date) order by b.date desc
sql语句分组统计出年月日下数据记录数目
原文：http://www.cnblogs.com/bornteam/p/4739707.html
