Question

我试图创建一个SQL来根据日期提取数据，现在有权使用where子句来获取我真正需要的东西我有下表和TVF：

/* dbo.weeks  -> column(weeknum), column(date)  **date is all Fridays** */
weeknum    date
  1     2001-09-21
  2     2001-09-28
  3     2001-10-05
 ...        ....
/* fnBenchMark(@weeknum)  -> display benchmark data based on weeknum */

这是我的代码：

SELECT  p.weeknum, p.date, q.companyid, q.index 
FROM dbo.Weeks AS p 
cross apply 
dbo.fnBenchmark(p.weeknum) as q 
where date = '2001-09-21'

/* Here is what I wish to add to above code but don't know how to do it */

if    
    date in dbo.Weeks column (date)  --if date on where clause is a Friday and it is on dbo.weeks table 
then run above code    
else 
    change date to LastFridayDate    --if date on where clause is Sat~Thur, then use previous Friday's date
then run above

例如，假设2001-09-21是星期五，如果我在where子句中输入 2001-09-24 ，我希望SQL运行＆＃34;其中date =＆＃34; 2001-09-21 ＆＃34;自2001-09-24以来，我进入的不是星期五＆＃34;

也许我应该创建另一个函数（SVF？），根据我输入的参数@date返回上周五的日期？然后使用：

where date = fnFridayCheck(@date I entered)

Answer 1

你可以使用

datepart(dw,getdate())

而不仅仅是storedprocedure或仅仅是一个查询

IF datepart(dw,getdate()) = 6
BEGIN
  something if it's a friday (because 6 in dateprart points to firday)
END
ELSE
BEGIN
  something else to do
END

SQL Server - 其中+ TVF / SVF，交叉应用，T-SQL

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