SQL-Server query to select last and previous information for multiple columns - sql

Question

After looking in Stackoverflow I cant find a solution to this problem.
I'm using this query:
SELECT *
FROM(
SELECT DISTINCT *
FROM Table_01
ORDER BY ID, StartDate
UNION ALL(
SELECT DISTINCT * FROM Table_02
ORDER BY ID, StartDate
)
UNION ALL (...
) a ORDER BY a.ID, a.StartDate
I got something like this, for each ID i would like to keep the last and previous date and other columns, to record a history
+------+------------+-----------+-------+-------+
| ID | StartDate | EndDate | Value | rate |
+------+------------+-----------+-------+-------+
| 1 | 2018-06-29 |2018-10-22 | 15 | 77.2 |
| 1 | 2018-04-28 |2018-06-21 | 23 | 55.3 |
| 1 | 2018-02-24 |2018-04-15 | 41 | 44.3 |
| 1 | 2017-06-29 |2017-11-29 | 55 | 44.1 |
| 2 | 2018-07-29 |2018-11-22 | 15 | 106.1 |
| 2 | 2018-03-28 |2018-07-21 | 23 | 10.8 |
| 2 | 2017-12-28 |2018-03-28 | 22 | 11.0 |
| 3 | 2017-09-28 |2018-01-28 | 11 | 87.09 |
| 3 | 2017-06-27 |2018-09-28 | 58 | 100 |
| ... | ... | ... | ... | ... |
+------+------------+-----------+-------+--------+
And I would like to have the next table, to keep the previous information
+------+------------+-----------+------------+-----------+-------+--------+-------+--------+
| ID | StartDate | EndDate | StartDateP | EndDateP | Value | rate | ValueP| rateP |
+------+------------+------------+-----------+-----------+-------+--------+-------+--------+
| 1 | 2018-06-29 |2018-10-22 | 2018-04-28 |2018-06-21 | 15 | 77.2 | 23 | 55.3 |
| 2 | 2018-07-29 |2018-11-22 | 2018-03-28 |2018-07-21 | 15 | 106.1 | 23 | 10.8 |
| 3 | 2017-09-28 |2018-01-28 | 2017-06-27 |2018-09-28 | 11 | 87.09 | 58 | 100 |
| ... | ... | ... | ... | ... | ... | ... | ... | ... |
+------+------------+-----------+------------+-----------+-------+--------+-------+--------+

Answer 1

If I understand you correctly you want the row with the latest start date combined with the row with the startdate just before that? This might do the trick
WITH results AS
(
SELECT *, ROW_NUMBER() OVER(PARTITION BY ID ORDER BY StartDate DESC) r
FROM (
-- start of your original query
SELECT DISTINCT *
FROM Table_01
ORDER BY ID, StartDate
UNION ALL
(
SELECT DISTINCT *
FROM Table_02
ORDER BY ID, StartDate
)
UNION ALL
(...) a
ORDER BY a.ID, a.StartDate
-- end of your original query
)
)
SELECT
r1.id, r1.startDate, r2.enddate,
r2.startDate startDateP, r2.enddate enddateP,
r1.value, r1.rate,
r2.value valueP, r2.rate rateP
FROM results r1
LEFT JOIN results r2 ON r2.id = r1.id AND r2.r = 2
WHERE r1.r = 1

Answer 2

Another option is using Row_Number() in concert with a conditional aggregation
Example
Select ID
,StartDate = max(case when RN=1 then StartDate end)
,EndDate = max(case when RN=1 then EndDate end)
,StartDateP = max(case when RN=2 then StartDate end)
,EndDateP = max(case when RN=2 then EndDate end)
,Value = max(case when RN=1 then Value end)
,Rate = max(case when RN=1 then Rate end)
,ValueP = max(case when RN=2 then Value end)
,RateP = max(case when RN=2 then Rate end)
From (
Select *
,RN = Row_Number() over (Partition By ID Order by EndDate Desc)
From YourTable
) A
Group By ID
Returns