如何按照时间段group by

季度就用月份运算一个新的值，然后group by 这个字段
(month-1)/4+1
1 2 3 4 ---> 1

5 6 7 8 ---> 2
然后，７天就用星期值，
mysql 有函数取某个日期　regdate 的月份或者星期数。

比如mongodb 就有这样的

db.sales.aggregate(
   [
     {
       $project:
         {
           year: { $year: "$date" },
           month: { $month: "$date" },
           day: { $dayOfMonth: "$date" },
           hour: { $hour: "$date" },
           minutes: { $minute: "$date" },
           seconds: { $second: "$date" },
           milliseconds: { $millisecond: "$date" },
           dayOfYear: { $dayOfYear: "$date" },
           dayOfWeek: { $dayOfWeek: "$date" },
           week: { $week: "$date" }
         }
     }
   ]
)