MSSQL - How to divide each month into 4 weeks? - sql-server-2008

Question

I have a query that is close to doing what I need:
select *
from
(
select DATEPART (YEAR, order_date) as theYear,
DATEPART (WEEK, order_date) as theWeek,
SUM (order_totalPrice) as totalSales
from orders_tbl
where order_date >= '01/01/2015'
group by DATEPART (YEAR, order_date), DATEPART (WEEK, order_date)
) as mySourceTable
pivot
(
sum (totalSales)
for theYear in ([2015], [2016], [2017])
) as myPivotTable
order by theWeek asc
This gives a result like:
Week 2015 2016 2017
----------------------------
1 $999 $999 $999
2 $999 $999 $999
3 $999 $999 $999
But this defines "weeks" as being 7 days starting on a certain day of the week. (I think Monday is the default).
What I really want to do is divide each month into 4 weeks, such that I'll have 48 "weeks" per year, like this:
Day of Month Week #
-----------------------
1-7 1
8-14 2
15-21 3
22+ 4
And my final output would look like:
Month Week 2015 2016 2017
----------------------------------------
1 1 $999 $999 $999
1 2 $999 $999 $999
1 3 $999 $999 $999
1 4 $999 $999 $999
2 1 $999 $999 $999
2 2 $999 $999 $999
I want to do this because it makes the most business sense for us.
How can I modify the above query to achieve this?
Stipulation 1: This is a query that I am calling from within a web application code (so, I think this rules out some T-SQL stuff... right?) Yes, I could use the web app code to do various loops or other manipulations, but is there a way to do this purely in a single SQL query?
Stipulation 2: I'm using MS SQL 2008 R2.

Answer 1

You can make use if the DAY functions which returns the day of the month.
DAY(order_date) AS DayOfMonth
Next you can build up your own logic like:
CASE WHEN DAY(order_date) >= 1 AND DAY(order_date) < 8 THEN 1
WHEN DAY(order_date) >= 8 AND DAY(order_date) < 15 THEN 2
WHEN DAY(order_date) >= 15 AND DAY(order_date) < 22 THEN 3
ELSE 4 END AS WeekNumber

Answer 2

If you want to devide month into weeks in Laravel following code may help you
public function weeksOfMonth($year = null, $month)
{
if($year == null ):
$year = Carbon::now()->year;
endif;
$date = Carbon::createFromDate($year,$month);
$j=1;
$week_array = [];
for ($i=1; $i <= $date->daysInMonth ; $i++) {
Carbon::createFromDate($year,$month,$i);
$start_date = Carbon::createFromDate($year,$month,$i)->startOfWeek()->toDateString();
$end_date = Carbon::createFromDate($year,$month,$i)->endOfweek()->toDateString();
$week_array[$j]['start_date'] = $start_date;
$week_array[$j]['end_date'] = $end_date;
$week_array[$j]['week'] = 'week'.$j;
$i+=7;
$j++;
}
return $week_array;
}