Monthly weights on a daily grain - sql

Question

I would like to write a tsql script that would display five columns. First column is date, second is the day of the week, third is how many of that day in a week exist in the current month, fourth is weight of the day and the fifth is the weight of the month (Mon through Wed get 15 each and Thu through Sun get 10 each). What's the easiest and fastest way to achieve that?
Example output:
Date Day_of_the_week Occurs_in_a_month Weight_of_the_day Weight_of_the_month
1/1/2015 Thursday 5 10 370
1/2/2015 Friday 5 10 370
1/3/2015 Saturday 5 10 370
1/4/2015 Sunday 4 10 370
1/5/2015 Monday 4 15 370
1/6/2015 Tuesday 4 15 370
1/7/2015 Wednesday 4 15 370
1/8/2015 Thursday 5 10 370
1/9/2015 Friday 5 10 370
1/10/2015 Saturday 5 10 370
1/11/2015 Sunday 4 10 370
1/12/2015 Monday 4 15 370
1/13/2015 Tuesday 4 15 370
1/14/2015 Wednesday 4 15 370
1/15/2015 Thursday 5 10 370
1/16/2015 Friday 5 10 370
1/17/2015 Saturday 5 10 370
1/18/2015 Sunday 4 10 370
1/19/2015 Monday 4 15 370
1/20/2015 Tuesday 4 15 370
1/21/2015 Wednesday 4 15 370
1/22/2015 Thursday 5 10 370
1/23/2015 Friday 5 10 370
1/24/2015 Saturday 5 10 370
1/25/2015 Sunday 4 10 370
1/26/2015 Monday 4 15 370
1/27/2015 Tuesday 4 15 370
1/28/2015 Wednesday 4 15 370
1/29/2015 Thursday 5 10 370
1/30/2015 Friday 5 10 370
1/31/2015 Saturday 5 10 370
2/1/2015 Sunday 4 10 340
2/2/2015 Monday 4 15 340
2/3/2015 Tuesday 4 15 340
2/4/2015 Wednesday 4 15 340
2/5/2015 Thursday 4 10 340
2/6/2015 Friday 4 10 340
2/7/2015 Saturday 4 10 340
2/8/2015 Sunday 4 10 340
2/9/2015 Monday 4 15 340
2/10/2015 Tuesday 4 15 340
2/11/2015 Wednesday 4 15 340
2/12/2015 Thursday 4 10 340
2/13/2015 Friday 4 10 340
2/14/2015 Saturday 4 10 340
2/15/2015 Sunday 4 10 340
2/16/2015 Monday 4 15 340
2/17/2015 Tuesday 4 15 340
2/18/2015 Wednesday 4 15 340
2/19/2015 Thursday 4 10 340
2/20/2015 Friday 4 10 340
2/21/2015 Saturday 4 10 340
2/22/2015 Sunday 4 10 340
2/23/2015 Monday 4 15 340
2/24/2015 Tuesday 4 15 340
2/25/2015 Wednesday 4 15 340
2/26/2015 Thursday 4 10 340
2/27/2015 Friday 4 10 340
2/28/2015 Saturday 4 10 340
.
.
.
.
Say between the years of 2015 and 2020.

Answer 1

Use recursive cte to build the date list.. the rest is just window functions
WITH cteDates AS (
SELECT CONVERT(DATE, '2015-01-01') AS [Date]
UNION ALL
SELECT DATEADD(DAY, 1, [Date])
FROM cteDates
WHERE DATEADD(DAY, 1, [Date]) < '2021-01-01'
),
cteWeights AS (
SELECT [Date],
DATENAME(weekday, [Date]) [Day_of_the_week],
COUNT(*) OVER (PARTITION BY DATEPART(MONTH, [Date]), DATEPART(YEAR, [Date]),DATENAME(weekday, [Date])) [Occurs_in_a_month],
(CASE WHEN DATENAME(weekday, [Date]) IN ('Monday', 'Tuesday', 'Wednesday') THEN 15 ELSE 10 END) [Weight_of_the_day]
FROM cteDates
)
SELECT *,
SUM([Weight_of_the_day]) OVER (PARTITION BY DATEPART(MONTH, [Date]), DATEPART(YEAR, [Date])) [ Weight_of_the_month]
FROM cteWeights
ORDER BY [Date]
OPTION (MAXRECURSION 0)