displaying reporting weeks - sql

Question

I dont know how to loop through so that the query displays all the weeks from the reporting date?
The code determines the Mon - Sun week then should insert the values in a temp table to then query the weeks. I have hard coded the report_date and its hould display more than one record.
any ideas
DECLARE #REPORT_DATE DATETIME, #WEEK_BEGINING VARCHAR(10)
SELECT #REPORT_DATE = '2011-01-01T00:00:00'
--SELECT #REPORT_DATE = GETDATE() -- should grab the date now.
SELECT #WEEK_BEGINING = 'MONDAY'
IF #WEEK_BEGINING = 'MONDAY'
SET DATEFIRST 1
ELSE IF #WEEK_BEGINING = 'TUESDAY'
SET DATEFIRST 2
ELSE IF #WEEK_BEGINING = 'WEDNESDAY'
SET DATEFIRST 3
ELSE IF #WEEK_BEGINING = 'THURSDAY'
SET DATEFIRST 4
ELSE IF #WEEK_BEGINING = 'FRIDAY'
SET DATEFIRST 5
ELSE IF #WEEK_BEGINING = 'SATURDAY'
SET DATEFIRST 6
ELSE IF #WEEK_BEGINING = 'SUNDAY'
SET DATEFIRST 7
DECLARE #WEEK_START_DATE DATETIME, #WEEK_END_DATE DATETIME
--GET THE WEEK START DATE
SELECT #WEEK_START_DATE = #REPORT_DATE - (DATEPART(DW, #REPORT_DATE) - 1)
--GET THE WEEK END DATE
SELECT #WEEK_END_DATE = #REPORT_DATE + (7 - DATEPART(DW, #REPORT_DATE))
PRINT 'Week Start: ' + CONVERT(VARCHAR, #WEEK_START_DATE)
PRINT 'Week End: ' + CONVERT(VARCHAR, #WEEK_END_DATE)
CREATE TABLE #WeekList
(
month_date date
)
DECLARE #Interval int = 1
INSERT INTO #WeekList SELECT #WEEK_START_DATE
WHILE #Interval < 1
BEGIN
INSERT INTO #WeekList SELECT DATEADD(MONTH, - #Interval, #WEEK_START_DATE)
SET #Interval = #Interval + 1
END
SELECT
--Create the month ID code:
#WEEK_START_DATE AS Start_Week, #WEEK_END_DATE AS End_Week
FROM #WeekList
ORDER BY Start_Week DESC
DROP TABLE #WeekList

Answer 1

Using DATEADD and updating your #interval initialization and updated loop logic:
DECLARE #REPORT_DATE DATETIME, #WEEK_BEGINING VARCHAR(10)
SELECT #REPORT_DATE = '2011-01-01T00:00:00'
--SELECT #REPORT_DATE = GETDATE() -- should grab the date now.
SELECT #WEEK_BEGINING = 'MONDAY'
IF #WEEK_BEGINING = 'MONDAY'
SET DATEFIRST 1
ELSE IF #WEEK_BEGINING = 'TUESDAY'
SET DATEFIRST 2
ELSE IF #WEEK_BEGINING = 'WEDNESDAY'
SET DATEFIRST 3
ELSE IF #WEEK_BEGINING = 'THURSDAY'
SET DATEFIRST 4
ELSE IF #WEEK_BEGINING = 'FRIDAY'
SET DATEFIRST 5
ELSE IF #WEEK_BEGINING = 'SATURDAY'
SET DATEFIRST 6
ELSE IF #WEEK_BEGINING = 'SUNDAY'
SET DATEFIRST 7
DECLARE #WEEK_START_DATE DATETIME, #WEEK_END_DATE DATETIME
--GET THE WEEK START DATE
SELECT #WEEK_START_DATE = #REPORT_DATE - (DATEPART(DW, #REPORT_DATE) - 1)
--GET THE WEEK END DATE
SELECT #WEEK_END_DATE = #REPORT_DATE + (7 - DATEPART(DW, #REPORT_DATE))
PRINT 'Week Start: ' + CONVERT(VARCHAR, #WEEK_START_DATE)
PRINT 'Week End: ' + CONVERT(VARCHAR, #WEEK_END_DATE)
DECLARE #Interval int = datediff(WEEK,getdate(),#WEEK_START_DATE)+1
SELECT Start_Week=#WEEK_START_DATE
, End_Week=#WEEK_END_DATE
INTO #WeekList
WHILE #Interval <= 0
BEGIN
set #WEEK_START_DATE=DATEADD(WEEK,1,#WEEK_START_DATE)
set #WEEK_END_DATE=DATEADD(WEEK,1,#WEEK_END_DATE)
INSERT INTO #WeekList values (#WEEK_START_DATE,#WEEK_END_DATE)
SET #Interval += 1;
END
SELECT *
FROM #WeekList
ORDER BY Start_Week DESC
DROP TABLE #WeekList
Results (top 5 and bottom 5 of list):
Start_Week End_Week
----------------------- -----------------------
2012-03-12 00:00:00.000 2012-03-18 00:00:00.000
2012-03-05 00:00:00.000 2012-03-11 00:00:00.000
2012-02-27 00:00:00.000 2012-03-04 00:00:00.000
2012-02-20 00:00:00.000 2012-02-26 00:00:00.000
2012-02-13 00:00:00.000 2012-02-19 00:00:00.000
...
2011-01-24 00:00:00.000 2011-01-30 00:00:00.000
2011-01-17 00:00:00.000 2011-01-23 00:00:00.000
2011-01-10 00:00:00.000 2011-01-16 00:00:00.000
2011-01-03 00:00:00.000 2011-01-09 00:00:00.000
2010-12-27 00:00:00.000 2011-01-02 00:00:00.000
As an aside, you could also use the date type instead of Datetime, if you don't need to store the time.

Answer 2

If you would like to list the weeks and the corresponding counts or sums, you can do this as follows
Sample data
myDate
----------
2012-03-15
2012-03-15
2012-03-15
2012-03-14
2012-03-14
2012-03-14
2012-03-14
2012-03-09
2012-03-09
2012-03-09
2012-03-08
2012-03-08
2012-03-08
2012-03-01
2012-03-01
2012-03-01
2012-03-01
2012-02-29
2012-02-29
2012-02-29
2012-02-29
2012-02-23
2012-02-23
2012-02-23
2012-02-22
2012-02-22
2012-02-22
2012-02-22
Script for sample data
create table #myTable(mydate Date)
insert into #myTable select DATEADD(day, -1, getdate())
insert into #myTable select DATEADD(day, -1, getdate())
insert into #myTable select DATEADD(day, -1, getdate())
insert into #myTable select DATEADD(day, -2, getdate())
insert into #myTable select DATEADD(day, -2, getdate())
insert into #myTable select DATEADD(day, -2, getdate())
insert into #myTable select DATEADD(day, -2, getdate())
insert into #myTable select DATEADD(day, -7, getdate())
insert into #myTable select DATEADD(day, -7, getdate())
insert into #myTable select DATEADD(day, -7, getdate())
insert into #myTable select DATEADD(day, -8, getdate())
insert into #myTable select DATEADD(day, -8, getdate())
insert into #myTable select DATEADD(day, -8, getdate())
insert into #myTable select DATEADD(day, -15, getdate())
insert into #myTable select DATEADD(day, -15, getdate())
insert into #myTable select DATEADD(day, -15, getdate())
insert into #myTable select DATEADD(day, -15, getdate())
insert into #myTable select DATEADD(day, -16, getdate())
insert into #myTable select DATEADD(day, -16, getdate())
insert into #myTable select DATEADD(day, -16, getdate())
insert into #myTable select DATEADD(day, -16, getdate())
insert into #myTable select DATEADD(day, -22, getdate())
insert into #myTable select DATEADD(day, -22, getdate())
insert into #myTable select DATEADD(day, -22, getdate())
insert into #myTable select DATEADD(day, -23, getdate())
insert into #myTable select DATEADD(day, -23, getdate())
insert into #myTable select DATEADD(day, -23, getdate())
insert into #myTable select DATEADD(day, -23, getdate())
Expected Result
Count WeekStart WeekEnd
----- ---------- ----------
7 2012-02-20 2012-02-24
8 2012-02-27 2012-03-02
6 2012-03-05 2012-03-09
7 2012-03-12 2012-03-16
How to do
SET DATEFIRST 1
SELECT
COUNT(*) [Count],
DATEADD(DD, -(DATEPART(DW, mydate)-1), mydate) [WeekStart],
DATEADD(DD, 7-(DATEPART(DW, mydate)+2), mydate) [WeekEnd]
FROM
#myTable
WHERE
DATEPART(dw, mydate) >= 1 AND DATEPART(dw, mydate) <= 5 -- only weekdays
GROUP BY
DATEADD(DD, -(DATEPART(DW, mydate)-1), mydate),
DATEADD(DD, 7-(DATEPART(DW, mydate)+2), mydate)
ORDER BY
DATEADD(DD, -(DATEPART(DW, mydate)-1), mydate)