SQL Server PIVOT on multiple columns is losing data - sql-server

Question

I've spent way too much time on this issue, and I'm not getting to the finish line. Please read this through before you run to a conclusion that this is a duplicate of all the other pivot with multiple columns on SO.
We have properties and units, with a table which keeps track of when something changed in the unit. We cannot change the structure of the table, as this is a vendor application.
Objective: Pull out the begin and end date for when a unit had an unavailable code of "model".
Issue: I need to filter out the dates where it was available in the middle, though that seems to omit one row of data each time (for unit 105).
what I've tried: PIVOT, CROSS APPLY in conjunction with LEAD/LAG
Here's a link to a SQLFiddle: http://sqlfiddle.com/#!6/29592/2/0
The rest of the question has the tsql from the SQLfiddle including the results which I got. The desired result is at the end.
Create table and insert sample data
DROP TABLE IF EXISTS testModelUnit;
CREATE TABLE testModelUnit(
propertykey INT NOT NULL
,unitNumber VARCHAR(10) NOT NULL
,rowStartDate DATETIME NOT NULL
,rowEndDate DATETIME NOT NULL
,unavailableCode varchar(10) NULL
,CONSTRAINT pk_testModelUnit PRIMARY KEY (propertykey, unitNumber, rowStartDate )
)
GO
INSERT INTO testModelUnit VALUES
(33,'105', '2010-11-11 00:00:00.000','2016-11-11 00:00:00.000','MODEL')
,(33,'105', '2016-11-11 00:00:00.000','2016-12-14 07:51:03.307','MODEL')
,(33,'105', '2016-12-14 07:51:03.307','2017-01-01 00:00:00.000',NULL)
,(33,'105', '2017-01-01 00:00:00.00','2017-03-21 12:21:13.703','MODEL')
,(33,'105', '2017-03-21 12:21:13.703','2017-04-21 12:21:13.703','MODEL')
,(33,'105', '2017-04-21 12:21:13.703','9999-12-31 00:00:00.000','MODEL')
,(33,'2606','2017-04-21 12:21:23.207','9999-12-31 00:00:00.000','MODEL')
,(33,'2606','2017-04-19 10:30:09.227','2017-04-21 12:21:23.207','MODEL')
,(33,'2703','2016-12-14 07:51:03.307','2017-04-19 10:29:47.970','MODEL')
,(33,'2703','2011-11-11 00:00:00.000','2016-12-14 07:51:03.307','MODEL')
GO
That gives you all the data which you need in order to test it, as unit 105 was available for a short period of time at the end of 2016.
Attempt 1 - use LEAD/LAG to determine if a date is the first in a series - then use multiple PIVOT statements
SELECT
propertykey
,unitNumber
,firstDate
,lastDate
FROM (
SELECT
propertykey
,unitNumber
,rowStartDate
,rowEndDate
,CASE
WHEN propertykey = LAG(propertykey,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate)
AND unitNumber = LAG(unitNumber,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate)
AND LAG(rowEndDate,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate) = rowStartDate THEN NULL
ELSE 'firstDate'
END ISFIRST
,CASE
WHEN propertykey = LEAD(propertykey,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate)
AND unitNumber = LEAD(unitNumber,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate)
AND LEAD(rowStartDate,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate) = rowEndDate THEN NULL
ELSE 'lastDate'
END ISLAST
FROM testModelUnit
WHERE UnavailableCode = 'model'
) SRC
PIVOT (
MAX(rowStartDate)
FOR isfirst in ([firstDate])
) as pivotFirst
PIVOT (
MAX(rowEndDate)
FOR islast in ([lastDate])
) as pivotLast
Results were:
propertykey unitNumber firstDate lastDate
33 105 NULL 9999-12-31 00:00:00.000
33 105 2010-11-11 00:00:00.000 NULL
33 105 2017-01-01 00:00:00.000 NULL
33 2606 NULL 9999-12-31 00:00:00.000
33 2606 2017-04-19 10:30:09.227 NULL
33 2703 NULL 2017-04-19 10:29:47.970
33 2703 2011-11-11 00:00:00.000 NULL
Issue is twofold: firstly, I have the NULLs in different rows, and secondly, I am missing an end date for unit 105 (by reversing the order of the two pivot statements, I reversed the issue, and I was then missing on start date)
Second attempt: use the LAG/LEAD as before, though this time use CROSS APPLY to get the first/last values into one column and then pivot the result
SELECT
propertykey
,unitNumber
,firstDate
,lastDate
FROM(
SELECT
propertykey
,unitNumber
,ca.col
,ca.value
FROM
(
SELECT
propertykey
,unitNumber
,rowStartDate
,rowEndDate
,CASE
WHEN propertykey = LAG(propertykey,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate)
AND unitNumber = LAG(unitNumber,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate)
AND LAG(rowEndDate,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate) = rowStartDate THEN NULL
ELSE 'firstDate'
END ISFIRST
,CASE
WHEN propertykey = LEAD(propertykey,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate)
AND unitNumber = LEAD(unitNumber,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate)
AND LEAD(rowStartDate,1,NULL) OVER (PARTITION BY propertykey,unitNumber ORDER BY rowStartDate) = rowEndDate THEN NULL
ELSE 'lastDate'
END ISLAST
FROM testModelUnit
WHERE UnavailableCode = 'model'
) sub
OUTER APPLY (
SELECT ISFIRST, rowStartDate
UNION ALL
SELECT ISLAST, rowEndDate
) CA (col, value)
WHERE col IS NOT NULL
)src
PIVOT
(
max(value)
for col in ([firstDate],[lastDate])
) AS pivoted
Result:
propertykey unitNumber firstDate lastDate
33 105 2017-01-01 00:00:00.000 9999-12-31 00:00:00.000
33 2606 2017-04-19 10:30:09.227 9999-12-31 00:00:00.000
33 2703 2011-11-11 00:00:00.000 2017-04-19 10:29:47.970
Issue: I got rid of the NULL rows, though I am still missing one record of data for 105
Desired result:
propertykey unitNumber firstDate lastDate
33 105 2010-11-11 00:00:00.000 2016-12-14 07:51:03.307
33 105 2017-01-01 00:00:00.000 9999-12-31 00:00:00.000
33 2606 2017-04-19 10:30:09.227 9999-12-31 00:00:00.000
33 2703 2011-11-11 00:00:00.000 2017-04-19 10:29:47.970

Answer 1

Are you looking query like below?
Select PropertyKey, UnitNumber, Min(RowStartDate) as FirstDate, Max(rowEndDate) as LastDate from (
Select *, Bucket = Row_number() over(partition by propertykey, unitnumber order by rowStartDate) -
Row_number() over(partition by propertykey, unitnumber, unavailablecode order by rowStartDate)
from testModelUnit
) a
Where a.unavailableCode is not null
group by propertykey, unitNumber, Bucket
Output as below:
+-------------+------------+-------------------------+-------------------------+
| PropertyKey | UnitNumber | FirstDate | LastDate |
+-------------+------------+-------------------------+-------------------------+
| 33 | 105 | 2010-11-11 00:00:00.000 | 2016-12-14 07:51:03.307 |
| 33 | 105 | 2017-01-01 00:00:00.000 | 9999-12-31 00:00:00.000 |
| 33 | 2606 | 2017-04-19 10:30:09.227 | 9999-12-31 00:00:00.000 |
| 33 | 2703 | 2011-11-11 00:00:00.000 | 2017-04-19 10:29:47.970 |
+-------------+------------+-------------------------+-------------------------+
Demo