Generate a list of dates between 2 dates for more than one record - sql

Question

I am trying to write SQL to generate the following data
Date Count
2018-09-24 2
2018-09-25 2
2018-09-26 2
2018-09-27 2
2018-09-28 2
2018-09-29 1
A sample of the base table I am using is
ID StartDate EndDate
187267 2018-09-24 2018-10-01
187270 2018-09-24 2018-09-30
So I'm trying to get a list of dates between 2 dates and then count how many base data records there are in each date.
I started using a temporary table and attempting to loop through the records to get the results but I'm not sure if this is the right approach.
I have this code so far
WITH ctedaterange
AS (SELECT [Dates] = (select ea.StartWork from EngagementAssignment ea where ea.EngagementAssignmentId IN(SELECT ea.EngagementAssignmentId
FROM EngagementLevel el INNER JOIN
EngagementAssignment ea ON el.EngagementLevelID = ea.EngagementLevelId
WHERE el.JobID = 15072 and ea.AssetId IS NOT NULL))
UNION ALL
SELECT [dates] + 1
FROM ctedaterange
WHERE [dates] + 1 < = (select ea.EndWork from EngagementAssignment ea where ea.EngagementAssignmentId IN(SELECT ea.EngagementAssignmentId
FROM EngagementLevel el INNER JOIN
EngagementAssignment ea ON el.EngagementLevelID = ea.EngagementLevelId
WHERE el.JobID = 15072 and ea.AssetId IS NOT NULL)))
SELECT [Dates], Count([Dates])
FROM ctedaterange
GROUP BY [Dates]
But I get this error
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.
I get correct results when the job I use only generates one record in the subselect in the where clause, ie:
SELECT ea.EngagementAssignmentId
FROM EngagementLevel el INNER JOIN
EngagementAssignment ea ON el.EngagementLevelID = ea.EngagementLevelId
WHERE el.JobID = 15047 and ea.AssetId IS NOT NULL
generates one record.
The results look like this:
Dates (No column name)
2018-09-24 02:00:00.000 1
2018-09-25 02:00:00.000 1
2018-09-26 02:00:00.000 1
2018-09-27 02:00:00.000 1
2018-09-28 02:00:00.000 1
2018-09-29 02:00:00.000 1
2018-09-30 02:00:00.000 1
2018-10-01 02:00:00.000 1

Answer 1

you can generate according to your range by changing from and to date
DECLARE
#DateFrom DATETIME = GETDATE(),
#DateTo DATETIME = '2018-10-30';
WITH DateGenerate
AS (
SELECT #DateFrom as MyDate
UNION ALL
SELECT DATEADD(DAY, 1, MyDate)
FROM DateGenerate
WHERE MyDate < #DateTo
)
SELECT
MyDate
FROM
DateGenerate;

Answer 2

Well, if you only have a low date range, you can use a recursive CTE as demonstrated in the other answers. The problem with a recursive CTE is with large ranges, where it starts to be ineffective - So I wanted to show you a different approach, that builds the calendar CTE without using recursion.
First, Create and populate sample table (Please save us this step in your future questions):
DECLARE #T AS TABLE
(
ID int,
StartDate date,
EndDate date
)
INSERT INTO #T (ID, StartDate, EndDate) VALUES
(187267, '2018-09-24', '2018-10-01'),
(187270, '2018-09-24', '2018-09-30')
Then, get the first start date and the number of dates you need in the calendar cte:
DECLARE #DateDiff int, #StartDate Date
SELECT #DateDiff = DATEDIFF(DAY, MIN(StartDate), Max(EndDate)),
#StartDate = MIN(StartDate)
FROM #T
Now, construct the calendar cte based on row_number (that is, unless you already have a numbers (tally) table you can use):
;WITH Calendar(TheDate)
AS
(
SELECT TOP(#DateDiff + 1) DATEADD(DAY, ROW_NUMBER() OVER(ORDER BY ##SPID)-1, #StartDate)
FROM sys.objects t0
-- unremark the next row if you don't get enough records...
-- CROSS JOIN sys.objects t1
)
Note that I'm using row_number() - 1 and therefor have to select top(#DateDiff + 1)
Finally - the query:
SELECT TheDate, COUNT(ID) As NumberOfRecords
FROM Calendar
JOIN #T AS T
ON Calendar.TheDate >= T.StartDate
AND Calendar.TheDate <= T.EndDate
GROUP BY TheDate
Results:
TheDate | NumberOfRecords
2018-09-24 | 2
2018-09-25 | 2
2018-09-26 | 2
2018-09-27 | 2
2018-09-28 | 2
2018-09-29 | 2
2018-09-30 | 2
2018-10-01 | 1
You can see a live demo on rextester.

Answer 3

Can you please try following SQL CTE query where I have used a SQL dates table function [dbo].[DatesTable] which produces a list of dates between min date and max date in the source table
;with boundaries as (
select
min(StartDate) minD, max(EndDate) maxD
from DateRanges
), dates as (
select
dates.[date]
from boundaries
cross apply [dbo].[DatesTable](minD, maxD) as dates
)
select dates.[date], count(*) as [count]
from dates
inner join DateRanges
on dates.date between DateRanges.StartDate and DateRanges.EndDate
group by dates.[date]
order by dates.[date]
The output is as expected

Answer 4

Try this: demo
WITH cte1
AS (SELECT id,sdate,edate from t
union all
select c.id,DATEADD(DAY, 1, c.sdate),c.edate from cte1 c where DATEADD(DAY, 1, c.sdate)<=c.edate
)
SELECT sdate,count(id) as total FROM cte1
group by sdate
OPTION (MAXRECURSION 0)
Output:
sdate total
2018-09-24 2
2018-09-25 2
2018-09-26 2
2018-09-27 2
2018-09-28 2
2018-09-29 2
2018-09-30 1