Get months from a date range comparing event date

Question

Hi All,
Below is the data
CREATE TABLE #Coverage(
EmployeeID INT,
EmployeeName VARCHAR(20),
CoverageName VARCHAR(50),
CoverageAmount Decimal,
CoveredBy VARCHAR(20),
EventDate DATETIME,
CoverageStartDate DATETIME,
CoverageEndDate DATETIME
INSERT INTO #coverage VALUES (8,'Lara','Employee + Children',213.60,'EmployeeContribution','2013-10-01','2013-10-01','2014-05-31'),
(8,'LAra','Employee + Children', 606.31 ,'CompanyContribution' ,'2013-10-01','2013-10-01','2014-05-31'),
(8,'LAra','Employee Only' ,0.00 ,'EmployeeContribution' ,NULL ,'2013-06-01','2014-05-31'),
(8,'LAra','Employee Only' ,431.55 ,'CompanyContribution' ,NULL ,'2013-06-01','2014-05-31'),
(8,'LAra','Employee Only' ,81.42 ,'EmployeeContribution' ,NULL ,'2012-06-01','2013-05-31'),
(8,'LAra','Employee Only' ,420.93 ,'CompanyContribution' ,NULL ,'2012-06-01','2013-05-31')
SELECT * FROM #Coverage
drop table #coverage
and expected out put for the year 2013
EmployeeID
EmployeeName
CoverageName
CoverageAmount
CoveredBy
Month
Year
8
Lara
Employee Only
81
Employee Contibution
1
2013
8
Lara
Employee Only
421
Company Contribution
1
2013
8
Lara
Employee Only
81
Employee Contibution
2
2013
8
Lara
Employee Only
421
Company Contribution
2
2013
8
Lara
Employee Only
81
Employee Contibution
3
2013
8
Lara
Employee Only
421
Company Contribution
3
2013
8
Lara
Employee Only
81
Employee Contibution
4
2013
8
Lara
Employee Only
421
Company Contribution
4
2013
8
Lara
Employee Only
81
Employee Contibution
5
2013
8
Lara
Employee Only
421
Company Contribution
5
2013
8
Lara
Employee Only
81
Employee Contibution
6
2013
8
Lara
Employee Only
421
Company Contribution
6
2013
8
Lara
Employee Only
81
Employee Contibution
7
2013
8
Lara
Employee Only
421
Company Contribution
7
2013
8
Lara
Employee Only
81
Employee Contibution
8
2013
8
Lara
Employee Only
421
Company Contribution
8
2013
8
Lara
Employee Only
81
Employee Contibution
9
2013
8
Lara
Employee Only
421
Company Contribution
9
2013
8
Lara
Employee +Children
214
Employee Contibution
10
2013
8
Lara
Employee +Children
606
Company Contribution
10
2013
8
Lara
Employee +Children
214
Employee Contibution
11
2013
8
Lara
Employee +Children
606
Company Contribution
11
2013
8
Lara
Employee +Children
214
Employee Contibution
12
2013
8
Lara
Employee +Children
606
Company Contribution
12
2013
Can any one help me out with this.
Thanks!

Answer 1

This gives your resultset.
I've added the cte to give a newenddate because your dataset doesn't close off the previous one in all cases and gave duplicates - you can remove this if it is a mistake in the data. Also you would need to add the employee to the partition to run on multiple
employees.
declare
@Coverage TABLE (
EmployeeID
INT,
EmployeeName
VARCHAR(20),
CoverageName
VARCHAR(50),
CoverageAmount
Decimal,
CoveredBy
VARCHAR(20),
EventDate
DATETIME,
CoverageStartDate
DATETIME,
CoverageEndDate
DATETIME
INSERT
INTO @Coverage
VALUES (8,'Lara','Employee + Children',213.60,'EmployeeContribution','2013-10-01','2013-10-01','2014-05-31'),
(8,'LAra','Employee
+ Children',  606.31
,'CompanyContribution'    
,'2013-10-01','2013-10-01','2014-05-31'),
(8,'LAra','Employee
Only'               
,0.00  ,'EmployeeContribution'   
,NULL  ,'2013-06-01','2014-05-31'),
(8,'LAra','Employee
Only'               
,431.55      
,'CompanyContribution'    
,NULL  ,'2013-06-01','2014-05-31'),
(8,'LAra','Employee
Only'               
,81.42 ,'EmployeeContribution'   
,NULL  ,'2012-06-01','2013-05-31'),
(8,'LAra','Employee
Only'               
,420.93      
,'CompanyContribution'    
,NULL  ,'2012-06-01','2013-05-31')
SELECT
* FROM
@Coverage
;with
ctee1 as
select
*, seq
= row_number()
over (partition
by coveredby
order by coveragestartdate)
from
@Coverage
,ctee
as
select
c1.*,
newenddte = coalesce(c2.coveragestartdate-1,
c1.coverageenddate)
from
ctee1 c1
left
join ctee1
c2
on
c1.coveredby
= c2.coveredby
and
c1.seq
= c2.seq-1
cte1 as
select
dtestrt =
convert(datetime,'20130101'),
dteend =
convert(datetime,'20131201')
,cte
as
select
dtestrt =
cte1.dtestrt,
dteend =
dateadd(mm,1,cte1.dtestrt)-1,
mth =
month(cte1.dtestrt),
yr =
year(cte1.dtestrt)
from cte1
union
all
select
dtestrt =
dateadd(mm,1,cte.dtestrt),
dteend =
dateadd(mm,2,cte.dtestrt)-1,
mth =
month(dateadd(mm,1,cte.dtestrt)),
yr =
year(dateadd(mm,1,cte.dtestrt))
from cte,
cte1 where
cte.dtestrt
< cte1.dteend-1
select
c.EmployeeID,
c.EmployeeName,
c.CoverageName,
c.CoverageAmount,
c.CoveredBy,
cte.mth,
cte.yr,
cte.dtestrt,
cte.dteend
from
cte
join
ctee c
on
cte.dtestrt
<= c.newenddte 
and cte.dteend
>= c.CoverageStartDate
order
by c.EmployeeID,
cte.dtestrt