SQL Server - Split a date range by a given date - sql-server

Question

I have a table that stores an Id and an effective period indicating when it is active
PortfolioId StartDate EndDate
1 2018-01-01 00:00:00.000 2018-05-31 00:00:00.000
2 2017-01-01 00:00:00.000 2018-05-31 00:00:00.000
I have another table that stores a component related to the above Id and that too has an effective period. Table 2 can have more that on entry for any given entry in table 1.
PortfolioComponentId PortfolioId SplitDate
1 1 2018-02-28 00:00:00.000
2 1 2018-03-31 00:00:00.000
3 2 2017-03-31 00:00:00.000
4 2 2017-09-20 00:00:00.000
5 2 2018-01-15 00:00:00.000
I have a period where I am running the query for
i.e
StartDate : 30-JUN-2017
End date : 15-MAY-2018
I have looking for a result like the below, where data in table 1 is split based on the data from table 2
PortfolioId StartDate EndDate
1 2018-01-01 00:00:00.000 2018-02-28 00:00:00.000
1 2018-03-01 00:00:00.000 2018-03-31 00:00:00.000 - Starts from End date + 1 from the prev row
1 2018-04-01 00:00:00.000 2018-05-15 00:00:00.000
2 2017-06-30 00:00:00.000 2017-09-20 00:00:00.000 - Starts from Seach date [Portfolio component Id 3 ignored as it falls outside of search date range]
2 2017-09-21 00:00:00.000 2018-01-15 00:00:00.000
2 2018-01-16 00:00:00.000 2018-05-15 00:00:00.000 - Ends by seach end date
Data setup - In case it helps
DECLARE #SearchStartDate DATETIME = '30-JUN-2017'
DECLARE #SearchEndDate DATETIME = '15-MAY-2018'
DECLARE #Portfolio TABLE
(
PortfolioId INT PRIMARY KEY IDENTITY(1,1),
StartDate DATETIME,
EndDate DATETIME
)
INSERT INTO #Portfolio
SELECT '01-JAN-2018', '31-MAY-2018'
INSERT INTO #Portfolio
SELECT '01-JAN-2017', '31-MAY-2018'
DECLARE #PortfolioComponents TABLE
(
PortfolioComponentId INT PRIMARY KEY IDENTITY(1,1),
PortfolioId INT,
SplitDate DATETIME
)
INSERT INTO #PortfolioComponents
SELECT 1, '28-FEB-2018'
INSERT INTO #PortfolioComponents
SELECT 1, '31-MAR-2018'
INSERT INTO #PortfolioComponents
SELECT 2, '31-MAR-2017'
INSERT INTO #PortfolioComponents
SELECT 2, '20-SEP-2017'
INSERT INTO #PortfolioComponents
SELECT 2, '15-JAN-2018'
SELECT * from #Portfolio
SELECT * from #PortfolioComponents

Answer 1

I believe I have got a result close to what I want, though not
the most ideal approach
the best approach from a performance perspective
DECLARE #Temp TABLE (BenchmarkDate Datetime, ComponentType int, PortfolioId INT)
INSERT INTO #Temp
SELECT StartDate , 1, PortfolioId FROM #Portfolio
UNION
SELECT EndDate , 2, PortfolioId FROM #Portfolio
INSERT INTO #Temp
SELECT SplitDate , 2, PortfolioId FROM #PortfolioComponents
UNION
SELECT SplitDate + 1 , 1, PortfolioId FROM #PortfolioComponents
DECLARE #Results TABLE
(
Id INT IDENTITY(1,1),
StartDate DATETIME,
EndDate DATETIME,
PortfolioId INT
)
INSERT INTO #Results
SELECT rset1.BenchmarkDate [Startdate],
( SELECT MIN(rset2.BenchmarkDate)
FROM #Temp rset2
WHERE rset2.ComponentType = 2
AND rset2.BenchmarkDate > rset1.BenchmarkDate
AND rset1.PortfolioId = rset2.PortfolioId) [Enddate],
rset1.PortfolioId
FROM #Temp rset1
WHERE rset1.ComponentType = 1
ORDER BY rset1.PortfolioId, rset1.BenchmarkDate
SELECT
CASE WHEN (#SearchStartDate BETWEEN StartDate AND EndDate ) THEN #SearchStartDate ELSE StartDate END StartDate,
CASE WHEN (#SearchEndDate BETWEEN StartDate AND EndDate) THEN #SearchEndDate ELSE EndDate END EndDate,
PortfolioId ,
(
SELECT PortfolioComponentId
FROM #PortfolioComponents pc
WHERE
(pc.PortfolioID = r.PortfolioId AND
(DATEADD(d, 1, pc.SplitDate) = r.StartDate ))
) PortfolioComponentId
FROM #Results r
WHERE
(#SearchStartDate < StartDate AND #SearchStartDate < EndDate AND #SearchEndDate > EndDate)
OR
(#SearchEndDate BETWEEN StartDate AND EndDate)
OR
(#SearchStartDate BETWEEN StartDate AND EndDate )