sqlalchemy日期格式化，date_format按月统计数据

问题：使用sqlalchemy如何按月统计数据

解决：使用原生sql语句，使用sqlalchemy的execute方法

方法：

sks_months = self.db.execute("select month(end_time) as month
   , sum(used_time) as used_time from student_kejian_stats where
    student_id = %d and end_time > %s group by month" % (cuid, year))
    .fetchall()

select DATE_FORMAT(create_time,'%Y%m%d') days,count(caseid) count from tc_case group by days;
select DATE_FORMAT(create_time,'%Y%u') weeks,count(caseid) count from tc_case group by weeks;
select DATE_FORMAT(create_time,'%Y%m') months,count(caseid) count from tc_case group by months;

注：因为使用的是mysql数据库，所以可以使用month方法

参考：

https://segmentfault.com/q/1010000002488768
http://www.cnblogs.com/joeblackzqq/p/4637654.html
http://linkyou.blog.51cto.com/1332494/751980/