sql - 如何选择一年中的每个星期一日期和每个星期五日期

Question

基本上我希望能够为一年中的每个星期选择星期一和星期五。

例如，本周即将到来的我想要 9/29/2014 和 10/3/2014，但我想要一年中的每个星期。

Answer 1

您可以使用带有数字的合适表，例如 master..spt_values 表作为范围生成的基础:

;WITH dates AS (
    SELECT DATEADD(DAY,number,CAST('2014-01-01' AS DATE)) d
    FROM master..spt_values WHERE TYPE = 'p'
    AND number < 366
    )

SELECT 
    Week = DATEPART(WEEK, d), 
    DayOfWeek = DATENAME(dw, d), 
    Date = d
FROM dates
WHERE DATENAME(dw, d) IN ('Monday', 'Friday')
-- or use datepart instead as datename might be specific to language
-- WHERE DATEPART(dw, d) IN (2,6)

示例输出:

Week        DayOfWeek                      Date
----------- ------------------------------ ----------
1           Friday                         2014-01-03
2           Monday                         2014-01-06
2           Friday                         2014-01-10
3           Monday                         2014-01-13
3           Friday                         2014-01-17
4           Monday                         2014-01-20
4           Friday                         2014-01-24
5           Monday                         2014-01-27
5           Friday                         2014-01-31