Create New Rows based on valid to and valid from dates - tsql

Question

I have a table that has account number, end of month valid from and end of month valid to columns.
What I need is a table that has account number and a column that has all the end of month dates of when the account was live, inclusive of end of month valid to. The Current Table looks like this
New table will need to be like this
I have tried using a calendar table and an CTE table type query but have had no success.
Any help would be great.

Answer 1

This can be achieved using Using multiple comma separated CTEs in a statement
Query
with t0 (i) AS (select 0 union all select 0 union all select 0 union all select 0 union all select 0 union all select 0),
t1 (i) AS (select 0 from t0 a inner join t0 b on a.i = b.i),
n (i) AS (select row_number()over(order by i) from t1),
Account_details (Account_number,valid_from,valid_to,mth,Live_date)As(
select Account_number,valid_from,valid_to, datediff(month,valid_from,valid_to ) mth, valid_from"Live_date"
from tbl1
union all
select Account_number,valid_from,valid_to, datediff(month,valid_from,valid_to ) mth, EOMONTH (dateadd(month,n.i,valid_from)) "Live_date"
from tbl1
inner join n on 1=1 and n.i between 1 and datediff(month,valid_from,valid_to )
)
select *
from Account_details
where Account_details.Account_number =1
order by Account_details.Account_number
Output
CTE Table t0, t1 and n will generate numbers. This is a best way to generate rows without any data.
Then the CTE table Account_details is used to pull data from the table.

Answer 2

Based on sql on the msdn thread how to get month end date between two dates.
DECLARE #Old AS Table (AccountNumber INT, ValidFrom DATE, ValidTo DATE)
DECLARE #New AS Table (AccountNumber INT, LiveDate DATE)
INSERT INTO #old
SELECT 1, '20130630', '20131130' UNION ALL
SELECT 2, '20130630', '20131231' UNION ALL
SELECT 3, '20120430', '20120531' UNION ALL
SELECT 4, '20170331', '20171130'
SELECT TOP 100 * FROM #old
DECLARE #AccountNumber INT, #ValidFrom DATE, #ValidTo DATE
DECLARE #Cursor CURSOR
SET #Cursor = CURSOR FOR
SELECT AccountNumber, ValidFrom, ValidTo
FROM #old
OPEN #Cursor
FETCH NEXT INTO #Cursor FROM #AccountNumber, #ValidFrom, #ValidTo
WHILE ##FETCH_STATUS = 0
BEGIN
;WITH cteEndMonthDates (MonthEndDate)
AS
(
SELECT eomonth(#ValidFrom) AS MonthEndDate
UNION ALL
SELECT eomonth( dateadd(day, 1, MonthEndDate)) AS MonthEndDate
FROM cteEndMonthDates
WHERE MonthEndDate < eomonth(#ValidTo)
)
INSERT INTO #new (AccountNumber, LiveDate)
SELECT #AccountNumber, MonthEndDate
FROM cteEndMonthDates
FETCH NEXT FROM #Cursor INTO #AccountNumber, #ValidFrom, #ValidTo
END
CLOSE #Cursor
DEALLOCATE #Cursor
SELECT * FROM #New
Edit: Or without the cursor
DECLARE #Old AS Table (AccountNumber INT, ValidFrom DATE, ValidTo DATE)
DECLARE #New AS Table (AccountNumber INT, LiveDate DATE)
INSERT INTO #old
SELECT 1, '20130630', '20131130' UNION ALL
SELECT 2, '20130630', '20131231' UNION ALL
SELECT 3, '20120430', '20120531' UNION ALL
SELECT 4, '20170331', '20171130' UNION ALL
SELECT 5, '20180430', '20190131' UNION ALL
SELECT 6, '20160430', '20180531'
SELECT TOP 100 * FROM #old
;WITH cteEndMonthDates (AccountNumber, MonthEndDate)
AS
(
SELECT AccountNumber, eomonth(ValidFrom) AS MonthEndDate
FROM #Old
UNION ALL
SELECT x.AccountNumber, eomonth( dateadd(day, 1, MonthEndDate)) AS MonthEndDate
FROM cteEndMonthDates x
JOIN #Old o ON o.AccountNumber = x.AccountNumber
WHERE MonthEndDate < eomonth(ValidTo)
)
SELECT AccountNumber, MonthEndDate
FROM cteEndMonthDates
order by AccountNumber, MonthEndDate

Answer 3

This should work.
;WITH Span AS (
SELECT
AccountNumber,
ValidFrom AS Valid
FROM dbo.Input
UNION ALL
SELECT
AccountNumber,
DATEADD(DAY, 1, Span.Valid) AS Valid
FROM Span
WHERE DATEADD(DAY, 1, Span.Valid) <= (SELECT ValidTo FROM dbo.Input WHERE AccountNumber = Span.AccountNumber)
)
SELECT * FROM Span
ORDER BY Span.AccountNumber, Span.Valid
OPTION (MAXRECURSION 0);