SQL查询按月计算计数

许多方法…在上一份工作中对许多应用程序来说对我来说效果很好的一种方法是建立时间表。

id - Year - Month   - StartStamp - End Stamp  1  - 2008 - January - 1/1/2008 00:00:00.000 - 1/31/2008 23:59:59.999

然后，您可以将其日期字段放在startstamp和endstamp之间的timeframes表中进行联接。

这样可以很容易地拉出某个时间段或所有时间段…

您的记录可能更简单，只需12条记录（即1月1日）并加入DATEPART（m，DateColumn）

select mon.monthNumber, mon.monthName,        count(a.*) as count1, count(b.*) as count2from months monleft join whatever1 a on DATEPART(m,a.Date) = mon.monthNumberleft join whatever2 b on DATEPART(m,b.Date) = mon.monthNumbergroup by mon.monthNumber, mon.monthName

您也可以临时执行月份 *** 作，如下所示：

select mon.monthNumber, mon.monthName,        count(a.*) as count1, count(b.*) as count2from (   select 1 as monthNumber, 'January' as monthName   union   select 2 as monthNumber, 'February' as monthName   union   select 3 as monthNumber, 'March' as monthName   union   ......etc.....) monleft join whatever1 a on DATEPART(m,a.Date) = mon.monthNumberleft join whatever2 b on DATEPART(m,b.Date) = mon.monthNumbergroup by mon.monthNumber, mon.monthName