How to Update Week Number in SQL? - sql

Question

I have a following which are displayed order by date. I want to group each weekseries as below.
Select tq.ID,
CONVERT(VARCHAR(10),tq.DateCreated,101)WeekDate,
DATENAME(WEEKDAY,tq.DateCreated)WeekDays,
CASE When DATEPART(WEEKDAY,tq.DateCreated)-1=0 THEN 7 ELSE DATEPART(WEEKDAY,tq.DateCreated)-1 END as WeekSerial
From #temp tq
Current Data:
ID WeekDate WeekDays WeekSerial WeekNumber
56 2012-03-01 00:00:00.000 Thursday 4 NULL
57 2012-03-02 00:00:00.000 Friday 5 NULL
58 2012-03-03 00:00:00.000 Saturday 6 NULL
59 2012-03-04 00:00:00.000 Sunday 7 NULL
62 2012-03-05 00:00:00.000 Monday 1 NULL
63 2012-03-06 00:00:00.000 Tuesday 2 NULL
64 2012-03-07 00:00:00.000 Wednesday 3 NULL
65 2012-03-08 00:00:00.000 Thursday 4 NULL
67 2012-03-09 00:00:00.000 Friday 5 NULL
68 2012-03-10 00:00:00.000 Saturday 6 NULL
69 2012-03-11 00:00:00.000 Sunday 7 NULL
70 2012-03-12 00:00:00.000 Monday 1 NULL
71 2012-03-13 00:00:00.000 Tuesday 2 NULL
73 2012-03-14 00:00:00.000 Wednesday 3 NULL
74 2012-03-15 00:00:00.000 Thursday 4 NULL
76 2012-03-16 00:00:00.000 Friday 5 NULL
77 2012-03-17 00:00:00.000 Saturday 6 NULL
78 2012-03-18 00:00:00.000 Sunday 7 NULL
Required Data:
ID WeekDate WeekDays WeekSerial WeekNumber
56 2012-03-01 00:00:00.000 Thursday 4 1
57 2012-03-02 00:00:00.000 Friday 5 1
58 2012-03-03 00:00:00.000 Saturday 6 1
59 2012-03-04 00:00:00.000 Sunday 7 1
62 2012-03-05 00:00:00.000 Monday 1 2
63 2012-03-06 00:00:00.000 Tuesday 2 2
64 2012-03-07 00:00:00.000 Wednesday 3 2
65 2012-03-08 00:00:00.000 Thursday 4 2
67 2012-03-09 00:00:00.000 Friday 5 2
68 2012-03-10 00:00:00.000 Saturday 6 2
69 2012-03-11 00:00:00.000 Sunday 7 2
70 2012-03-12 00:00:00.000 Monday 1 3
71 2012-03-13 00:00:00.000 Tuesday 2 3
73 2012-03-14 00:00:00.000 Wednesday 3 3
74 2012-03-15 00:00:00.000 Thursday 4 3
76 2012-03-16 00:00:00.000 Friday 5 3
77 2012-03-17 00:00:00.000 Saturday 6 3
78 2012-03-18 00:00:00.000 Sunday 7 3
So, I want to group these values under weeknumber which must start from 1 for WeekSerial number ranges from 1 to 7.
NOTE: The week day starts from Monday to Sunday so its numbered from 1 through 7. i.e 1=Monday, 2=Tuesday and so on...!
Update:
INSERT INTO #Temp(KioskCount,KioskAmount,KioskAverage,WeekDate,WeekDays,WeekSerial)
Select COUNT(tq.quoteid)KioskCount,
SUM(tq.PriceQuote) [KioskAmount],
SUM(tq.PriceQuote) / COUNT(tq.QuoteID) [KioskAverage],
CONVERT(VARCHAR(10),tq.DateCreated,101)WeekDate,
DATENAME(WEEKDAY,tq.DateCreated)WeekDays,
CASE When DATEPART(WEEKDAY,tq.DateCreated)-1=0 THEN 7 ELSE DATEPART(WEEKDAY,tq.DateCreated)-1 END as WeekSerial
from tbl_Quotes tq
where
tq.QuoteStatusID <> 12 --remove void transactions
group by CONVERT(VARCHAR(10),tq.DateCreated,101),DATENAME(WEEKDAY,tq.DateCreated),DATEPART(WEEKDAY,tq.DateCreated)-1
order by 4

Answer 1

It is unclear actually what did you expect
You have already a WeekDate filed i think the date are correct and based on that you are filled your weekday field
then simply you can loop through the dates and update your week number using the WeekDate
i can provide an example with that
DECLARE #DATE DATETIME
DECLARE #count int
DECLARE #i int
SET #i=56// you can find your first id via query too
SET #count=(select COUNT(WeekDays) from tablename)
WHILE #i<=#count
BEGIN
SET #DATE =(select WeekDate from tablename where ID=#i)
update tablename set WeekNumber=(
SELECT DATEPART(WEEK, #DATE) -
DATEPART(WEEK, DATEADD(MM, DATEDIFF(MM,0,#DATE), 0))+ 1 AS WEEK_OF_MONTH)
where ID=#i
set #i=#i + 1
END;
it will update all your weeknumber field with corresponding number

Answer 2

Probably this helps you:
First you need to check the first of the day in your database
SELECT ##DATEFIRST
By default SUNDAY is first day of week (US). So you need to change it to 1 (Monday)
SET DATEFIRST 1
More inforamtion about SET DATEFIRST
In SQL Server by using DATEPART built-in function you can get the number of week in a year
SELECT DATAPART(WEEK, WeekDate)
Also you can get YEAR of your selected datetime
SELECT DATAPART(YEAR, WeekDate)
If you run these two queries for your first row (Let's say Week number 1)
SELECT DATEPART(WEEK, '2012-03-01 00:00:00.000') -- Output = 10
SELECT DATEPART(YEAR, '2012-03-01 00:00:00.000') -- Output = 2012
But this week should be your week number 1.
So you can easily subtract 2012 from your YEAR then multiply it by 52 (because we have 52 weeks in a year)
Substract 9 from your WEEKNUMBER
Add the numbers you get from above
(YEAR - 2012) * 52 + (WEEK - 9)
So by running this you can get the actual result
SELECT (DATEPART(YEAR, WeekDate) - 2012) * 52 + DATEPART(WEEK, WeekDate) - 9 AS WeekNumber
FROM yourTable