Count how many times a time occurs within a date range - sql

Question

I could not think of a good way to phrase this question to search properly if its already been asked.
I'm looking for a way in SQL 2008 R2 to count how many times 6pm occurs between two datetime values.
For example between '2017-04-17 19:00:00' and '2017-04-19 17:00:00' 6pm only occurs once even though the times span 3 different days.
Between '2017-04-17 18:00:00' and '2017-04-19 18:00:00' it occurs 3 times whilst also spanning 3 days.
Heres a really silly made up expression of what I want for illustration.
timecount(hh, 6, min(datefield), max(datefield))
Thank you

Answer 1

A simple query to count:
DECLARE #StartDate datetime = '2017-04-17 18:00:00'
DECLARE #EndDate datetime = '2017-04-19 18:00:00'
SELECT
CASE
WHEN CAST(#StartDate AS time) <= '18:00' AND CAST(#EndDate AS time) >= '18:00'
THEN datediff(day, #StartDate, #EndDate) + 1
WHEN CAST(#StartDate AS time) <= '18:00' AND CAST(#EndDate AS time) < '18:00'
THEN datediff(day, #StartDate, #EndDate)
WHEN CAST(#StartDate AS time) > '18:00' AND CAST(#EndDate AS time) >= '18:00'
THEN datediff(day, #StartDate, #EndDate)
ELSE datediff(day, #StartDate, #EndDate) - 1
END AS TotalCount

Answer 2

This will give you each hour and the number of occurences:
select datepart(hh, DateColumn) as TheHours, count(*) as occurs
from MyTable
where DateColumn between #SomeDate and #SomeOtherDate
group by datepart(hh, DateColumn)
Or just for 6pm:
select count(*)
from MyTable
where datepart(hh, DateColumn) = 18
and DateColumn between #SomeDate and #SomeOtherDate

Answer 3

DECLARE
#Time time = '18:00',
#From datetime = '2017-04-17 18:00:00',
#To datetime = '2017-04-19 18:00:00'
SELECT
CASE
-- Same date
WHEN DATEDIFF(DAY, #From, #To) = 0 THEN
CASE WHEN CAST(CAST(#From AS date) AS datetime) + #Time BETWEEN #From AND #To THEN 1 ELSE 0 END
-- Not same date
WHEN #From <= #To THEN
CASE WHEN #Time >= CAST(#From AS time) THEN 1 ELSE 0 END
+ DATEDIFF(DAY, #From, #To) - 1
+ CASE WHEN #Time <= CAST(#To AS time) THEN 1 ELSE 0 END
-- Invalid range
ELSE 0
END AS CountOfTime

Answer 4

Try below formula I have tried with different scenario and it works, let me know if I miss any scenario and not work as per your requirement.
DECLARE #firstDate Datetime='17-Apr-2017 17:00:00'
DECLARE #secondDate Datetime='17-Apr-2017 18:59:00'
SELECT
CASE WHEN DATEDIFF(day,#firstDate,#secondDate)=0
THEN IIF(CAST(#firstDate AS TIME) <='18:00' AND DATEPART(hh,#secondDate) >=18,1,0)
ELSE
CASE WHEN
(
CAST(#firstDate AS TIME) <='18:00' AND CAST(#secondDate AS TIME) <'18:00'
OR
CAST(#firstDate AS TIME) >'18:00' AND CAST(#secondDate AS TIME) >='18:00'
)
THEN DATEDIFF(day,#firstDate,#secondDate)
WHEN CAST(#firstDate AS TIME) <='18:00' AND CAST(#secondDate AS TIME) >='18:00' THEN DATEDIFF(day,#firstDate,#secondDate)+1
ELSE DATEDIFF(day,#firstDate,#secondDate)-1
END
END AS TotalCount

Answer 5

Try the below script, using CTE
DECLARE #F_DATE AS DATETIME = '2017-04-17 19:00:00'
,#T_DATE AS DATETIME = '2017-04-19 17:00:00'
;WITH CTE
AS (
SELECT (CASE WHEN DATEPART(HH,#F_DATE) <= 18
THEN #F_DATE
ELSE (CASE WHEN DATEDIFF(DAY,#F_DATE,#T_DATE) > 0
THEN DATEADD(DAY,1,#F_DATE) END)
END) AS CDATE
UNION ALL
SELECT DATEADD(DAY,1,CDATE)
FROM CTE
WHERE DATEADD(DAY,1,CDATE) <= #T_DATE
)
SELECT COUNT(CDATE) DATE_COUNT
FROM CTE
OPTION ( MAXRECURSION 0 )

Answer 6

Here's the count of every 6pm between two datetime:
DECLARE #StartDate datetime
DECLARE #EndDate datetime
set #StartDate = '2017-04-17 19:00:00'
set #EndDate = '2017-04-19 17:00:00'
;WITH cte1 (S) AS (
SELECT 1 FROM (VALUES (1), (1), (1), (1), (1), (1), (1), (1), (1), (1)) n (S)
),
cte2 (S) AS (SELECT 1 FROM cte1 AS cte1 CROSS JOIN cte1 AS cte2),
cte3 (S) AS (SELECT 1 FROM cte1 AS cte1 CROSS JOIN cte2 AS cte2)
select count(datepart(hour,result)) as count from
(SELECT TOP (DATEDIFF(hour, #StartDate, #EndDate) + 1)
result = DATEADD(hour, ROW_NUMBER() OVER(ORDER BY S) - 1, #StartDate)
FROM cte3) as res where datepart(hour,result) = 18
Here's the detailed view of 6pm between two datetime:
DECLARE #StartDate datetime
DECLARE #EndDate datetime
set #StartDate = '2017-04-17 19:00:00'
set #EndDate = '2017-04-19 17:00:00'
;WITH cte1 (S) AS (
SELECT 1 FROM (VALUES (1), (1), (1), (1), (1), (1), (1), (1), (1), (1)) n (S)
),
cte2 (S) AS (SELECT 1 FROM cte1 AS cte1 CROSS JOIN cte1 AS cte2),
cte3 (S) AS (SELECT 1 FROM cte1 AS cte1 CROSS JOIN cte2 AS cte2)
select result,datepart(hour,result) from
(SELECT TOP (DATEDIFF(hour, #StartDate, #EndDate) + 1)
result = DATEADD(hour, ROW_NUMBER() OVER(ORDER BY S) - 1, #StartDate)
FROM cte3) as res where datepart(hour,result) = 18

Answer 7

Here gives the count between any date ranges
declare #time datetime='06:00:00'
declare #startDate datetime='04/20/2017 05:00:00'
declare #enddate datetime='04/21/2017 05:00:00'
SELECT
case
WHEN datediff(ss,#time, convert(time(0),#startDate)) <=0 and datediff(ss,#time, convert(time(0),#enddate)) >=0
THEN datediff(dd,#startDate,#enddate) +1
WHEN (datediff(ss,#time, convert(time(0),#startDate)) <=0 and
datediff(ss,#time, convert(time(0),#enddate)) <=0
OR
datediff(ss,#time, convert(time(0),#startDate))> 0 and
datediff(ss,#time, convert(time(0),#enddate)) >0
OR
datediff(ss,#time, convert(time(0),#startDate))> 0 and datediff(ss,#time, convert(time(0),#enddate)) <=0
)
then datediff(dd,#startDate,#enddate)
ELSE
datediff(dd,#startDate,#enddate)-1
END