sql - SQL中如何计算两个日期之间 "Tuesdays"的个数？

Question

我想弄清楚如何计算 TSQL 中两个日期之间的“星期二”数？

“星期二”可以是任何值。

Answer 1

谢谢 t-clausen.dk，节省了我几天时间。
要获得每天的实例数:

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, -6, @to)/7-datediff(day, -5, @from)/7 AS TUE,
 datediff(day, -5, @to)/7-datediff(day, -4, @from)/7 AS WED,
 datediff(day, -4, @to)/7-datediff(day, -3, @from)/7 AS THU,
 datediff(day, -3, @to)/7-datediff(day, -2, @from)/7 AS FRI,
 datediff(day, -2, @to)/7-datediff(day, -1, @from)/7 AS SAT,
 datediff(day, -1, @to)/7-datediff(day, 0, @from)/7 AS SUN