SQL Server related question - sql-server

Question

I have this thing that i need to do and some advices will be greatly appreciated.
I have a SQL server table with some phone calls.For each phone call i have the start and end time.
What i need to accomplish: a stored procedure which for a certain period of time, let's say 5 hours at a x interval, lets say 2 minutes returns the number of connected calls.
Something like:
Interval Nr of Calls Connected
01-01-2010 12:00:00 - 01-01-2010 12:05:00 30
01-01-2010 12:05:01 - 01-01-2010 12:10:00 10
.............
Which will be the fastest way to do that? Thank you for your help

Answer 1

This will work for intervals that have calls ...
Declare #datetimestart datetime
Declare #interval int
Set #datetimestart = '2009-01-01 12:00:00'
Set #interval = 5 --in minutes
Select
[start_interval], [end_interval] , count([start_interval]) as [calls]
From
(
Select
DateAdd( Minute,Floor(DateDiff(Minute,#datetimestart,[date])/#interval)*#interval
,#datetimestart) ,
DateAdd( Minute,#interval + Floor(DateDiff(Minute,#datetimestart,[date])/#interval)*#interval
,#datetimestart)
From yourTable
) As W([start_interval],[end_interval])
group by [start_interval], [end_interval]
This will work for all intervals regardless of number of calls..
Declare #datetimestart datetime, #datetimeend datetime, #datetimecurrent datetime
Declare #interval int
Set #datetimestart = '2009-01-01 12:00:00'
Set #interval = 10
Set #datetimeend = (Select max([date]) from yourtable)
SET #datetimecurrent = #datetimestart
declare #temp as table ([start_interval] datetime, [end_interval] datetime)
while #datetimecurrent < #datetimeend
BEGIN
insert into #temp select (#datetimecurrent), dateAdd( minute, #interval, #datetimecurrent)
set #datetimecurrent = dateAdd( minute, #interval, #datetimecurrent)
END
Select
*
From
(
Select
[start_interval],[end_interval], count(d.[start_time])
From #temp t left join yourtable d on d.[start_time] between t.[start_interval] and t.[end_interval]
) As W([start_interval],[end_interval], [calls])

Answer 2

I Altered Gaby's example a little to do What you expected
Declare #datetimeend datetime
,#datetimecurrent datetime
,#interval int
Set #interval = 10
Set #datetimeend = (Select max([end_time]) from Calls)
SET #datetimecurrent = '2010-04-17 14:20:00'
declare #temp as table ([start_interval] datetime, [end_interval] datetime)
while #datetimecurrent < #datetimeend
BEGIN
insert into #temp select (#datetimecurrent), dateAdd( minute, #interval, #datetimecurrent)
set #datetimecurrent = dateAdd( minute, #interval, #datetimecurrent)
END
Select
[start_interval],[end_interval], count(d.id) [COUNT]
From #temp t
left join Calls d on
d.end_time >= t.start_interval
AND d.start_time <= t.end_interval
GROUP BY [start_interval],[end_interval]
used this to create the table and fill it
CREATE TABLE dbo.Calls
(
id int NOT NULL IDENTITY (1, 1),
start_time datetime NOT NULL,
end_time datetime NULL,
caller nvarchar(50) NULL,
receiver nvarchar(50) NULL
) ON [PRIMARY]
GO
ALTER TABLE dbo.Calls ADD CONSTRAINT
PK_Calls PRIMARY KEY CLUSTERED
(
id
) ON [PRIMARY]
GO
DECLARE #I INT
SET #I = 0
WHILE #I < 100
BEGIN
INSERT INTO Calls
(start_time, end_time)
select
DATEADD(HOUR,-#I,DATEADD(MINUTE,-10,GETDATE()))
,DATEADD(HOUR,-#I,DATEADD(MINUTE,-9,GETDATE()))
UNION
select
DATEADD(HOUR,-#I,DATEADD(MINUTE,-9,GETDATE()))
,DATEADD(HOUR,-#I,DATEADD(MINUTE,-8,GETDATE()))
UNION
select
DATEADD(HOUR,-#I,DATEADD(MINUTE,-8,GETDATE()))
,DATEADD(HOUR,-#I,DATEADD(MINUTE,-7,GETDATE()))
UNION
select
DATEADD(HOUR,-#I,DATEADD(MINUTE,-7,GETDATE()))
,DATEADD(HOUR,-#I,DATEADD(MINUTE,-6,GETDATE()))
UNION
select
DATEADD(HOUR,-#I,DATEADD(MINUTE,-6,GETDATE()))
,DATEADD(HOUR,-#I,DATEADD(MINUTE,-5,GETDATE()))
UNION
SELECT
DATEADD(HOUR,-#I,DATEADD(MINUTE,-5,GETDATE()))
,DATEADD(HOUR,-#I,DATEADD(MINUTE,-4,GETDATE()))
UNION
select
DATEADD(HOUR,-#I,DATEADD(MINUTE,-4,GETDATE()))
,DATEADD(HOUR,-#I,DATEADD(MINUTE,-3,GETDATE()))
UNION
select
DATEADD(HOUR,-#I,DATEADD(MINUTE,-3,GETDATE()))
,DATEADD(HOUR,-#I,DATEADD(MINUTE,-2,GETDATE()))
UNION
select
DATEADD(HOUR,-#I,DATEADD(MINUTE,-2,GETDATE()))
,DATEADD(HOUR,-#I,DATEADD(MINUTE,-1,GETDATE()))
UNION
select
DATEADD(HOUR,-#I,DATEADD(MINUTE,-1,GETDATE()))
,DATEADD(HOUR,-#I,DATEADD(MINUTE,-0,GETDATE()));
SET #I = #I + 1
END
Done in SQL Server 2008
but the script would work in other versions

Answer 3

I would use a Numbers pivot table to get the time intervals and then count all calls which overlapped the interval:
SELECT Intervals.IntervalStart
,Intervals.IntervalEnd
,COUNT(*)
FROM (
SELECT DATEADD(MINUTE, Numbers * 2, #StartTime) AS IntervalStart
,DATEADD(MINUTE, (Numbers + 1) * 2, #StartTime) AS IntervalEnd
FROM Numbers
WHERE Numbers BETWEEN 0 AND (5 * 60 / 2)
) AS Intervals
LEFT JOIN Calls
ON Calls.CallEnd >= Intervals.IntervalStart
AND Calls.CallStart < Intervals.IntervalEnd
GROUP BY Intervals.IntervalStart
,Intervals.IntervalEnd
To get the empty intervals, you would need to LEFT JOIN to this from another "Intervals" derived table.

Answer 4

How about this approach:
select Year(StartTime) as Year, Month(StartTime) as Month, Day(StartTime) as Day, datepart(hh, StartTime) as Hour, datepart(mm, StartTime) / 2 as TwoMinuteSegment, count(*)
from MyTable
where StartDate between '01-01-2010 12:00:00' and '01-01-2010 17:00:00'
group by Year(StartTime), Month(StartTime), Day(StartTime), datepart(hh, StartTime), datepart(mm, StartTime) / 2