Group continuous date ranges from same table SQL Server - sql

Question

I have following data:
CREATE TABLE #Rate
(
RateId Bigint
,PropertyId Bigint
,StartDate DATETIME
,EndDate DATETIME
)
INSERT INTO #Rate VALUES (100,1000,'2015-01-01','2010-01-11')
INSERT INTO #Rate VALUES (100,1000,'2015-01-12','2015-02-02')
INSERT INTO #Rate VALUES (100,1000,'2015-02-11','2015-02-25')
INSERT INTO #Rate VALUES (100,1002,'2015-01-01','2010-01-11')
INSERT INTO #Rate VALUES (100,1002,'2015-01-12','2015-02-02')
INSERT INTO #Rate VALUES (101,1000,'2015-02-11','2015-02-25')
INSERT INTO #Rate VALUES (101,1000,'2015-01-01','2010-01-11')
INSERT INTO #Rate VALUES (101,1000,'2015-01-12','2015-02-02')
And I need this result set
100 1000 '2015-01-01' '2015-02-02'
100 1000 '2015-02-11' '2015-02-25'
100 1002 '2015-01-01' '2015-02-02'
101 1002 '2015-01-01' '2015-02-02'
I need to group by RateId and propertyId and continuous date range for this. I have done this using cursor but I don't want cursor because we have lots of records.
If we can create view out of it that will be great :)
Thanks.

Answer 1

Changing all the 2010 with 2015 in your data the actual resultset you can expect is
RateId PropertyId StartDate EndDate
-------------------- -------------------- ---------- ----------
100 1000 2015-01-01 2015-02-02
100 1000 2015-02-11 2015-02-25
100 1002 2015-01-01 2015-02-02
101 1000 2015-01-01 2015-02-02
101 1000 2015-02-11 2015-02-25
this question is quite similar to find start and stop date for contiguous dates in multiple rows so I'll use my answer to that one as a template
WITH D AS (
SELECT RateId, PropertyId, StartDate, EndDate
, _Id = ROW_NUMBER() OVER (PARTITION BY RateId, PropertyId
ORDER BY StartDate, EndDate)
FROM #Rate
), N AS (
SELECT m.RateId, m.PropertyId, m.StartDate, m.EndDate
, LastStop = p.EndDate
FROM D m
LEFT JOIN D p ON m.RateID = p.RateId
AND m.PropertyId = p.PropertyId
AND m._Id = p._Id + 1
), B AS (
SELECT RateId, PropertyId, StartDate, EndDate, LastStop
, Block = SUM(CASE WHEN LastStop Is Null Then 1
WHEN LastStop + 1 < StartDate Then 1
ELSE 0
END)
OVER (PARTITION BY RateId, PropertyId ORDER BY StartDate, EndDate)
FROM N
)
SELECT RateId, PropertyId
, MIN(StartDate) StartDate
, MAX(EndDate) EndDate
FROM B
GROUP BY RateId, PropertyId, Block
ORDER BY RateId, PropertyId, Block;
D generates a row counter to avoid to use triangular join.
N get the previous EndDate in the same RateID, PropertyID group for every row.
B generate a sequence number for every block
The main query aggregates the data in B to get the wanted resultset.

Answer 2

Assuming you are using SQL Server 2012+, you can take the following approach:
Find all the records that do not overlap with the prev record. These begin a range.
Count the number of such records before any given record. These assign a constant value to the range.
Use this as a grouping factor.
The query looks like:
select rateid, propertyid, min(startdate) as startdate, max(enddate) as enddate
from (select r.*,
sum(case when preved < startdate then 1 else 0 end) over (partition by rateid, propertyid order by startdate) as grp
from (select r.*,
lag(enddate) over (partition by rateid, propertyid order by enddate) as preved
from #Rate r
) r
) r
group by rateid, propertyid, grp;
EDIT:
In SQL Server 2008, you can do something similar:
with r as (
select r.*,
(case when exists (select 1
from #rate r2
where r2.rateid = r.rateid and r2.propertyid = r.propertyid and
(r2.startdate <= dateadd(1 day, r.enddate) and
r2.enddate >= r.startdate)
) then 0 else 1 end) as isstart
from #Rate r join
#Rate r2
)
select rateid, propertyid, min(startdate) as startdate, max(enddate) as enddate
from (select r.*,
(select sum(isstart)
from r r2
where r2.rateid = r.rateid and r2.propertyid = r.propertyid
r2.startdate <= r.startdate) as grp
from r
) r
group by rateid, propertyid, grp;