Get Room Price of Overlapping dates [closed] - sql

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I have table in this structure:
id accom_id room_type_id date_from date_to price_per_room
3 1 2 2017-09-01 2017-09-10 70.00
5 1 2 2017-09-11 2017-09-20 100.00
Lets say I want to stay from 2017-09-07 to 2017-09-15. So with DATEDIFF I need to count how many days the price is 70 and how many days the price is 100. At the end I want to show the total.
Can anyone help me build this query? I hope its clear what ask!

Answer 1

Assuming no overlapping ranges are defined, and assuming that all of the ranges given are meant to be inclusive, we can obtain the data using a CTE and then a simple matter of aggregation:
declare #t table (date_from date,date_to date, price_per_room int)
insert into #t (date_from,date_to,price_per_room) values
('20170901','20170910',70.00 ),
('20170911','20170920',100.00)
declare #Start date
declare #End date
select #Start = '20170907',#End = '20170915'
;With IncludedPeriods as (
select
CASE WHEN #Start > date_from THEN #Start ELSE date_from END as fromDT,
CASE WHEN #End < date_to THEN #End ELSE date_to END as ToDT,
price_per_room
from
#t
where
date_from <= #End and
#Start <= date_to
)
select
SUM(price_per_room * (1 + DATEDIFF(day,fromDT,ToDT)))
from
IncludedPeriods
Note that we're adding one to the DATEDIFF result since it counts transitions, but I'm assuming that a period from '20170911' to '20170911' should count as one day and longer periods similarly.
Unlike some of the other answers which attempt to enumerate various "cases" for overlaps, this uses the simple rule - two periods overlap if the first starts before the second ends and if the second starts before the first ends - that's the logic applied in the where clause inside the CTE. To determine the extent of the overlap, we take the later of the two start dates and the earlier of the two end dates - that's what the CASE expressions are doing. If we had scalar MIN and MAX functions that operated on dates I'd prefer to use those but no such functions built into SQL Server.

Answer 2

In SQL Server you can do this:
select dateadd(d, number, '20170801')
from master.dbo.spt_values
where type='P' and (number <= datediff(d, '20170801', '20170810'))
You calculate the total days (in the where clause) and you select the numbers from 0 to total days (master.dbo.spt_values is a helpful table in SQL Server). Otherwise you can create a table with ascending numbers from 0 to ?). And then you add to the startdate the number. So you get all days of the booking:
2017-08-01
2017-08-02
2017-08-03
2017-08-04
2017-08-05
2017-08-06
2017-08-07
2017-08-08
2017-08-09
2017-08-10
Then you can join your given price_table on date_from and date_to and you can calculate your sum.
EDIT: Just to complete it... :-)
SELECT SUM(price_per_room)
FROM master.dbo.spt_values
LEFT OUTER JOIN room_prices AS rp ON (date_from <= DATEADD(d, number, my_start_date) AND DATEADD(d, number, my_start_date) <= date_to)
WHERE type='P' AND (number <= DATEDIFF(d, my_start_date, my_end_date))

Answer 3

I would suggest using a Date table(table containing all dates) or a derived table to populate these dates(you can find it online easily) like this:
SELECT p.id,p.room_type_id,sum(p.price_per_room)
FROM(
SELECT t.date,s.price_per_room,s.id,s.room_type_id
FROM (DATES QUERY \ DATE_TABLE) t
LEFT JOIN s.yourTable
ON(t.date between s.date_from and s.date_to)) p
WHERE p.id = YourID and p.room_type_id = YourTypeId
AND p.date between yourStartDate and yourEndDate
GROUP BY p.id,p.room_type_id
That populate a row for each date inside the range of dates for the price, so it will know how much is the price per day, and then just sum the price between your desired dates.

Answer 4

You can use a calendar or dates table for this sort of thing.
Without taking the actual step of creating a table, you can use an adhoc tables of dates with a common table expression like so:
declare #fromdate date = '20170907';
declare #thrudate date = '20170915';
;with n as (select n from (values(0),(1),(2),(3),(4),(5),(6),(7),(8),(9)) t(n))
, dates as (
select top (datediff(day, #fromdate, #thrudate)+1)
[Date]=convert(date,dateadd(day,row_number() over(order by (select 1))-1,#fromdate))
from n as deka cross join n as hecto cross join n as kilo
cross join n as tenK cross join n as hundredK
order by [Date]
)
select total_price = sum(price_per_room)
from dates d
inner join t
on d.date >= t.date_from
and d.date <= t.date_to
rextester demo: http://rextester.com/MCF52261
returns:
+-------------+
| total_price |
+-------------+
| 780 |
+-------------+
For a more detailed breakdown of the price and dates, you can swap the above select for this one:
select
fromdate = min(date)
, thrudate = max(date)
, days = count(*)
, price_per_room = avg(price_per_room)
, total = sum(price_per_room)
from dates d
inner join t
on d.date >= t.date_from
and d.date <= t.date_to
group by grouping sets ((price_per_room),())
rextester demo: http://rextester.com/NKZD1468
returns:
+------------+------------+------+----------------+-------+
| fromdate | thrudate | days | price_per_room | total |
+------------+------------+------+----------------+-------+
| 2017-09-07 | 2017-09-10 | 4 | 70 | 280 |
| 2017-09-11 | 2017-09-15 | 5 | 100 | 500 |
| 2017-09-07 | 2017-09-15 | 9 | 86 | 780 |
+------------+------------+------+----------------+-------+
Number and Calendar table reference:
Generate a set or sequence without loops - 2 - Aaron Bertrand
The "Numbers" or "Tally" Table: What it is and how it replaces a loop - Jeff Moden
Creating a Date Table/Dimension in sql Server 2008 - David Stein
Calendar Tables - Why You Need One - David Stein
Creating a date dimension or calendar table in sql Server - Aaron Bertrand

Answer 5

Using UNION ALL for all four possible cases may do the job as well
SELECT SUM(x.p)
FROM
(
SELECT (DATEDIFF(DAY, #from, date_to)+1)* price p
FROM tab
WHERE date_to BETWEEN #from AND #to AND NOT date_from BETWEEN #from AND #to
UNION ALL
SELECT ISNULL(SUM((DATEDIFF(DAY, date_from, date_to)+1)* price), 0) p
FROM tab
WHERE date_to BETWEEN #from AND #to AND date_from BETWEEN #from AND #to
UNION ALL
SELECT (DATEDIFF(DAY, date_from, #to)+1)* price p
FROM tab
WHERE date_from BETWEEN #from AND #to AND NOT date_to BETWEEN #from AND #to
UNION ALL
-- in the case that the (#from, #to) interval is completely in one row interval
SELECT (DATEDIFF(DAY, #from, #to)+1)* price p
FROM tab
WHERE date_from <= #from AND date_to >= #to
)x;
sqlfiddle demo