SQL Cut Stretch Date into various stretchs - sql

Question

I have a large stretch of dates in one table and some dates to cut in other table.
With this I need to get another table with all the stretchs inside the large one cut by the others dates.
I have this for the moment:
DECLARE #UTCSTARTDATE DATETIME='2020-01-20 00:00:00.00'
DECLARE #UTCENDDATE DATETIME='2020-01-20 04:00:00.00'
DECLARE #T1 TABLE
(
StartTime DATETIME,
EndTime DATETIME,
table_id int
)
DECLARE #T2 TABLE
(
CutTime DATETIME,
table2_id int
)
INSERT INTO #T1 SELECT #UTCSTARTDATE,#UTCENDDATE,1
INSERT INTO #T2 SELECT myCut,myID FROM (VALUES('2020-01-20 01:00:00.00',1),('2020-01-20 02:30:00.00',1),('2020-01-20 03:00:00.00',2))t2(myCut,myID)
SELECT * FROM #T1
SELECT * FROM #T2 order by CutTime ASC
DECLARE #STRETCHHOURSTABLE TABLE
(
startDate DATETIME,
endDate DATETIME
);
;WITH DATESPLITTER AS
(
SELECT
StartTime AS stretchStartDate,
(SELECT TOP(1) CutTime FROM #T2 where CutTime < EndTime AND table_id = table2_id order by CutTime ASC) AS stretchEndDate,
EndTime AS RealEndTime,
table_id AS RealID
FROM #T1
UNION ALL
SELECT
stretchEndDate,
(SELECT TOP(1) CutTime FROM #T2 where CutTime > stretchEndDate AND CutTime < RealEndTime AND table2_id = RealID order by CutTime ASC) AS stretchEndDate,
RealEndTime,
RealID
FROM DATESPLITTER
WHERE stretchEndDate < #UTCENDDATE
)
INSERT INTO #STRETCHHOURSTABLE (startDate, endDate)
SELECT
stretchStartDate,
CASE
WHEN #UTCENDDATE < stretchEndDate THEN #UTCENDDATE
ELSE stretchEndDate
END
FROM DATESPLITTER
SELECT * FROM #STRETCHHOURSTABLE

Answer 1

This seems to basically be lead() after union all:
select dt, lead(dt) over (order by dt)
from ((select v.dt
from #t1 t1 cross apply
(values (t1.startTime), (t1.endTime)) v(dt)
) union all
(select t2.cuttime
from #t2 t2
)
) t
Here is a db<>fiddle.

Answer 2

Try this, I have made changes:
DECLARE #UTCSTARTDATE DATETIME='2020-01-20 00:00:00.00'
DECLARE #UTCENDDATE DATETIME='2020-01-20 04:00:00.00'
DECLARE #T1 TABLE( StartTime DATETIME, EndTime DATETIME, table_id int);
DECLARE #T2 TABLE ( CutTime DATETIME, table2_id int);
INSERT INTO #T1 SELECT #UTCSTARTDATE,#UTCENDDATE,1
INSERT INTO #T2 VALUES('2020-01-20 01:00:00.00',1),('2020-01-20 02:30:00.00',1),('2020-01-20 03:00:00.00',2);
SELECT * FROM #T1
SELECT * FROM #T2 order by CutTime ASC;
DECLARE #STRETCHHOURSTABLE TABLE (startDate DATETIME, endDate DATETIME);
WITH DATESPLITTER AS
(
SELECT
StartTime AS stretchStartDate,
(select cuttime from (SELECT row_number() over(partition by table2_id order by CutTime ASC) rn, CutTime FROM #T2 where CutTime < EndTime AND table_id = table2_id)a
where a.rn = 1) AS stretchEndDate,
EndTime AS RealEndTime,
table_id AS RealID
FROM #T1
UNION ALL
SELECT
stretchEndDate,
ISNULL((select cuttime from (SELECT row_number() over(partition by table2_id order by CutTime ASC) rn, CutTime FROM #T2 where CutTime > stretchEndDate AND CutTime < RealEndTime AND table2_id = RealID)a
where a.rn = 1), RealEndTime) AS stretchEndDate,
RealEndTime,
RealID
FROM DATESPLITTER
WHERE stretchEndDate < #UTCENDDATE
)
INSERT INTO #STRETCHHOURSTABLE (startDate, endDate)
SELECT stretchStartDate,
CASE
WHEN #UTCENDDATE < stretchEndDate THEN #UTCENDDATE
ELSE stretchEndDate
END as sommm
FROM DATESPLITTER
SELECT * FROM #STRETCHHOURSTABLE