如何计算TSQL中两个日期之间的“星期二”数量？

我想弄清楚如何计算Tsql中两个日期之间“星期二”的数量？

“星期二”可能是任何价值.

解决方法

谢谢t-clausen.dk,保存了几天.
为了得到每天的实例：

declare @from datetime= '3/1/2013' 
declare @to datetime  = '3/31/2013' 


select 
 datediff(day,-7,@to)/7-datediff(day,-6,@from)/7 AS MON,datediff(day,-5,@from)/7 AS TUE,-4,@from)/7 AS WED,-3,@from)/7 AS THU,-2,@from)/7 AS FRI,-1,@from)/7 AS SAT,@from)/7 AS SUN