Subtition of cursor for combining tables with time periods - sql

Question

I have to combine two tables into one but I have to take validation dates into consideriation. For instance having two tables:
Address
ID AddressValue ValidFrom ValidTo
----------- --------------- ----------------------- -----------------------
1 Pink Street 2010-01-01 00:00:00.000 2010-01-20 00:00:00.000
2 Yellow Street 2010-01-20 00:00:00.000 2010-02-28 00:00:00.000
Phone
ID PhoneValue ValidFrom ValidTo
----------- ------------ ----------------------- -----------------------
1 123456789 2010-01-01 00:00:00.000 2010-01-15 00:00:00.000
2 987654321 2010-01-16 00:00:00.000 2010-01-31 00:00:00.000
I need to do combine them into new one:
NewSystem
ID NewPhone NewAddress ValidFrom ValidTo Version
----------- ----------- --------------- ----------------------- ----------------------- -------
1 123456789 Pink Street 2010-01-01 00:00:00.000 2010-01-15 00:00:00.000 4
2 NULL Pink Street 2010-01-15 00:00:00.000 2010-01-16 00:00:00.000 3
3 987654321 Pink Street 2010-01-16 00:00:00.000 2010-01-20 00:00:00.000 2
4 987654321 Yellow Street 2010-01-20 00:00:00.000 2010-01-31 00:00:00.000 1
5 NULL Yellow Street 2010-01-31 00:00:00.000 2010-02-28 00:00:00.000 0
The idea is quite simple. I create periods based on dates and then query each table in subqueries. I pasted my solution here: http://pastebin.com/cdKePA9X.
Right now I am trying to get rid of the cursor but I failed. I tried to use CTE but without success. Maybe someone of you faced similar problem or know how to combine these tables into one without using cursor. I pasted the 'create table' scripts here: http://pastebin.com/BeRspb6K.
Thank you in advanced.

Answer 1

First, construct new date ranges by merging the date ranges from the source tables. Second, for each new date range, lookup the valid data in the source tables.
WITH
old_ranges(d1,d2) AS (
SELECT ValidFrom,ValidTo FROM #Address UNION
SELECT ValidFrom,ValidTo FROM #Phone
),
new_ranges(d1,d2) AS (
SELECT d,LEAD(d) OVER(ORDER BY d)
FROM (
SELECT DISTINCT d
FROM old_ranges
UNPIVOT(d FOR dx IN (d1,d2)) p
) t
)
SELECT
ROW_NUMBER() OVER (ORDER BY d1) AS ID,
NewPhone,
NewAddress,
d1 AS ValidFrom,
d2 AS ValidTo
FROM new_ranges
OUTER APPLY (
SELECT PhoneValue AS NewPhone
FROM #Phone
WHERE ValidFrom <= d1 AND ValidTo >= d2
) x1
OUTER APPLY (
SELECT AddressValue AS NewAddress
FROM #Address
WHERE ValidFrom <= d1 AND ValidTo >= d2
) x2
WHERE d2 IS NOT NULL