基于星期几的SQL自动选择日期范围

Question

--This is using SQL

I Have tried and failed at this a few times,

I have a sales table with an order date in the following format '2014-05-15 00:00:00.000'

I would like to have a report that runs on the basis that if @today is less than Friday, show last weeks date range, if @today is Saturday or Sunday, then use this weeks date range

assuming I only want to see the fields SalesOrder and OrderDate

Thanks in advance,

Dean

Answer 1

Tweak to your hearts content (running this in SQL Server Management Studio will display messages with the correct outputs). Use the variables to filter your SELECT statement and remove the PRINT operators:

DECLARE @ReportDate DATETIME
DECLARE @StartOfWeek DATETIME
DECLARE @DayOfWeek INT 

SET @ReportDate = '2014-05-15 00:00:00.000' --This will be your variable in report builder
SET @DayOfWeek = DATEPART(dw,@ReportDate)

/* 
Take away the day of the week from the report date to
get the beginning of that week.
*/

--Adjust the +1 to mark the start of your week (ie. +2 makes Monday the start)
SET @StartOfWeek = DATEADD(dd, (-(@DayOfWeek) + 1), @Reportdate)

--Now do stuff based on the report date (set the beginning of the week)
IF @DayOfWeek BETWEEN 2 AND 5 --Friday is day 6 (Sunday is first day in SQL and the BETWEEN clause is inclusive)
BEGIN
    PRINT 'Monday to Thursday' --This line can be removed
    /* Now minus 7 to get the beginning of the previous week */
    SET @StartOfWeek = DATEADD(dd, -7, @StartOfWeek)
END
---------------------------------------------------
/*
This entire box is optional (can be removed) but just for demonstration purposes to
show that the date stuff works
*/

IF @DayOfWeek = 6 --Friday is day 6 
BEGIN
    PRINT 'Friday'
END
IF @DayOfWeek IN (7,1) --Saturday day 7, Sunday day 1
BEGIN
    PRINT 'Saturday or Sunday'
END
---------------------------------------------------

--This is where your SELECT statement goes (instead of PRINT operators below)
PRINT 'StartOfWeek = ' + CAST(@StartOfWeek AS NVARCHAR(255))
PRINT 'EndOfWeek = ' + CAST(DATEADD(dd,7,@StartOfWeek) AS NVARCHAR(255))