Extract the percent days from a specific month - sql-server

Question

I have a table like this one - changes table:
Table 1:
id start_date end_date s_g r_c s_c
111 1/1/15 25/5/2015 A1 1 0
111 26/05/2015 31/12/9999 Z1 1 2
222 1/1/14 10/2/2015 Q1 1 0
222 11/2/2015 31/12/9999 R1 1 0
And I need to build an montly output for 2015 like this:
id month s_g r_c _s_c percent
111 1 A1 1 0 100%
111 2 A1 1 0 100%
111 3 A1 1 0 100%
111 4 A1 1 0 100%
111 5 A1 1 0 83.33%
111 5 Z1 1 2 16.67%
111 6 Z1 1 2 100%
111 7 Z1 1 2 100%
111 8 Z1 1 2 100%
222 1 Q1 1 0 100%
222 2 Q1 1 0 35.71%
222 2 R1 1 0 64.29%
222 3 R1 1 0 100%
222 4 R1 1 0 100%
222 5 R1 1 0 100%
222 6 R1 1 0 100%
222 7 R1 1 0 100%
222 8 R1 1 0 100%
I need this month only for year 2015.
Any idea how can I build this thing? just assum that those are the only case.

Answer 1

You could try this.
DECLARE #Month_2015 TABLE
(
Date1 Date,
Date2 Date
)
INSERT INTO #Month_2015
select '2015-01-01','2015-01-31'
union all
select '2015-02-01','2015-02-28'
union all
select '2015-03-01','2015-03-31'
union all
select '2015-04-01','2015-04-30'
union all
select '2015-05-01','2015-05-31'
union all
select '2015-06-01','2015-06-30'
...
With CTE as
(
Select ID, date1, s_g, r_c, s_c,
le = case when start_date < Date2 AND End_date > DATE1 THEN Datediff(d,
(case when start_date < date1 THEN date1 else start_date end),
(case when end_date < date2 THEN end_date else date2 end)
Else 0
end,
m = DATEDIFF (d, date1, date2)
from
Table1, #Month_2015
)
Select ID, Month(date1), s_g, r_c, s_c, (le*100.0 / m)
from CTE
Where le > 0
order by ID, Month(date1), s_g, r_c, s_c

Answer 2

Try this. It worked for me based on your table ##
DECLARE #TableRezult TABLE (id INT,month INT,s_g varchar(2),r_c INT,s_c INT, MonthPercentage varchar(25))
DECLARE #month INT=1
WHILE #month<=12
BEGIN
INSERT INTO #TableRezult
SELECT id,#month,s_g,r_c,s_c,
CASE WHEN (end_date >= dateadd(m,1,convert(varchar,#month)+'/1/2015') OR end_date='12/31/2015')
AND ([START_DATE]<=convert(varchar,#month)+'/1/2015') THEN '100%' ELSE
CASE WHEN end_date >= convert(varchar,#month)+'/1/2015' AND end_date < dateadd(m,1,convert(varchar,#month)+'/1/2015') THEN convert(VARCHAR ,Day(end_date)*100.0/DAY(EOMONTH(start_date)))+'%'
WHEN start_date >= convert(varchar,#month)+'/1/2015' AND start_date < dateadd(m,1,convert(varchar,#month)+'/1/2015') THEN convert(varchar,(DAY(EOMONTH(start_date))-Day(start_date))*100.0/DAY(EOMONTH(start_date)))+'%'
ELSE '0%' END
END FROM Table1 WHERE MONTH([START_DATE])<=#month AND MONTH(end_date)>=#month
SET #month=#month+1
END
SELECT * FROM #TableRezult ORDER BY id,[MONTH]

Answer 3

since it is not fully explain,i am posting half solution,after clearing doubts calculation can be corrected.
declare #Table1 table (id int,start_date datetime,end_date datetime
, s_g varchar(20), r_c int, s_c int )
insert into #Table1 values
(111 ,'2015-01-01','2015-5-25','A1', 1, 0 )
,(111 ,'2015-05-26','9999-12-31','Z1', 1, 2 )
,(222 ,'2014-01-01','2015-02-10','Q1', 1, 0 )
,(222 ,'2015-02-11','9999-12-31','R1', 1, 0 )
DECLARE #year INT = 2015
;WITH CTE
AS (
SELECT id
,s_g
,r_c
,s_c
,CASE
WHEN datepart(year, start_date) = #year
THEN start_date
WHEN datepart(year, start_date) < #year
THEN CAST(#year AS CHAR(4)) + '-' + '01' + '-' + '01'
WHEN datepart(year, start_date) > #year
THEN CAST(#year AS CHAR(4)) + '-' + '12' + '-' + '31'
END startdate
,CASE
WHEN datepart(year, end_date) = #year
THEN end_date
WHEN datepart(year, end_date) < #year
THEN CAST(#year AS CHAR(4)) + '-' + '01' + '-' + '01'
WHEN datepart(year, end_date) > #year
THEN CAST(#year AS CHAR(4)) + '-' + '12' + '-' + '31'
END enddate
FROM #table1
)
,CTE1
AS (
SELECT A.id
,A.s_g
,A.r_c
,A.s_c
,A.startdate
,A.enddate
,DATEPART(month, A.startdate) MonthList
FROM CTE A
UNION ALL
SELECT A.id
,A.s_g
,A.r_c
,A.s_c
,dateadd(month, 1, A.startdate)
,A.enddate
,a.MonthList + 1
FROM CTE1 A
WHERE A.MonthList < DATEPART(month, a.enddate)
)
--select * from cte1
SELECT *
,CASE
WHEN datediff(month, startdate, enddate) >= 1
THEN 100
ELSE (datepart(day, enddate) / cast(datepart(day, dateadd(day, - 1, dateadd(month, (datediff(month, 0, enddate) + 1), 0))) AS DECIMAL(4, 2))) * 100
END
FROM cte1
ORDER BY id
,s_g
,monthlist