在SQL中计算两个日期之间的持续时间

Question

I'm having some difficulty with an SQL query for reporting machine efficiency from a CNC monitoring system. The monitoring software records the duration the machines are in different states like machining, stopped, out of work setup etc. I want to total up the duration of these states for each machine per day to determine their efficiency.

Each state is given a start and end time I initially thought it would be a simple case of calculating the difference between the two dates but its not that simple. The problem is a state can start late one day and end in the early hours of the next which making it difficult to calculate state duration per day.

Here's a link to an Excel file that contains sample data https://dl.dropboxusercontent.com/u/71259257/example%20dataset.xlsx

I have come up with a fairly messy solution, I was going to use this as a basis to create a scheduled stored procedure that outputs the processed data to a separate table.

Here's my query

DECLARE @date DATE;
SET @Date= '16 June 2015';

SELECT 
    Name, State, 
    CASE 
        WHEN LEFT(CONVERT(VARCHAR, StartDate, 120), 10) = @Date 
             AND LEFT(CONVERT(VARCHAR, EndDate, 120), 10) = @Date 
          THEN dbo.CalculateReportDuration(StartDate, EndDate) 
    END as Duration
FROM 
    [emc].[dbo].[TMB_MachineStateReport]
WHERE 
    CONVERT(Date, StartDate) = @Date 
    AND CONVERT(Date, EndDate) = @Date 

UNION ALL

SELECT 
    Name, State,
    dbo.CalculateReportDuration( LEFT(CONVERT(VARCHAR, EndDate, 120), 10) + ' 00:00:00.0000000 +00:00', EndDate)  as Duration
FROM 
    [emc].[dbo].[TMB_MachineStateReport]
WHERE 
    CONVERT(Date, EndDate) = @Date 
    AND CONVERT(Date, StartDate) < @Date 

UNION ALL

SELECT 
    Name, State,
    dbo.CalculateReportDuration(StartDate, LEFT(CONVERT(VARCHAR, StartDate, 120), 10) + ' 23:59:59.9999999 +00:00')
FROM 
    [emc].[dbo].[TMB_MachineStateReport]
WHERE 
    CONVERT(Date, EndDate) > @Date 
    AND CONVERT(Date, StartDate) = @Date

What I want to know is does anyone have any better ideas? Ideally I'd like to create view but currently I'm relying on an SQL variable to hold a date value that I was going to increment all dates in the table using a while loop.

Code for CalculateReportDuration function

USE [emc]
GO
/****** Object:  UserDefinedFunction [dbo].[CalculateReportDuration]    Script Date: 06/20/2015 10:23:21 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER FUNCTION [dbo].[CalculateReportDuration]
            (
                @start DATETIMEOFFSET(7),
                @end DATETIMEOFFSET(7)
            )
            RETURNS INT
            AS
            BEGIN
                RETURN CAST(ROUND(DATEDIFF(SECOND, @start, @end) / 60.0, 0) AS INT) 
            END

Any help is greatly appreciated

Answer 1

You can simply use DATEDIFF() on your two dates.

Here is a simple example:

SELECT DATEDIFF(minutes, GETDATE(), DATEADD(hours,2,GETDATE()))

Read more here .

As the OP stated in the comments, he want's to have a row for each day. This means the time should be split per day and afterwards a calculation should be done.

Here is the code to achieve this. Just keep in Mind, due to the fact that it's done with a CTE you should be aware of statements which are over 100 days. ;-) Otherwise you need to adjust MAX_RECURSION .

IF(OBJECT_ID(N'tempdb..#timing') IS NOT NULL )
    DROP TABLE #timing

-- Create demo data
CREATE TABLE #timing(id int identity(1,1), startdate datetime, enddate datetime)

INSERT INTO #timing(startdate, enddate)
VALUES (DATEADD(day,-1,GETDATE()),DATEADD(MINUTE,10,GETDATE())), -- time spanning 1 day + 10 min
        (DATEADD(MINUTE,-70,GETDATE()),GETDATE()), -- spanning the current date just over 70 minutes
        (DATEADD(day,-3,GETDATE()),GETDATE()) -- spanning 3 days

        SELECT t.startdate, t.enddate, CONVERT(date,t.startdate), CONVERT(date,t.enddate) FROM #timing as t

;WITH cte AS(
    SELECT id, t.startdate as orig_startdate, t.enddate as orig_enddate,
        t.startdate, 
        DATEADD(SECOND,-1,CONVERT(datetime,DATEADD(day,1,CONVERT(date,t.startdate)))) as enddate,
        1 as iteration
    FROM #timing as t
    WHERE CONVERT(date, t.startdate) <> CONVERT(date, t.enddate)
    UNION ALL
    SELECT c.id, c.orig_startdate, c.orig_enddate, 
        CONVERT(datetime,DATEADD(day,c.iteration,CONVERT(date,c.orig_startdate))) as startdate,
        CASE WHEN CONVERT(date,DATEADD(day,c.iteration,CONVERT(date,c.orig_startdate)))
                = CONVERT(date, c.orig_enddate)
             THEN c.orig_enddate
             ELSE DATEADD(SECOND,-1,CONVERT(datetime,DATEADD(day,c.iteration+1,CONVERT(date,c.orig_startdate))))
        END as enddate,
        c.iteration+1 as iteration
    FROM cte as c
    WHERE DATEADD(day,c.iteration,CONVERT(date,c.orig_startdate)) <= CONVERT(date, c.orig_enddate)
) 
SELECT data.id, data.startdate, data.enddate, data.currentDate, data.minutesCurrentDay
FROM (
    SELECT c.id, c.orig_startdate as startdate, c.orig_enddate as enddate, 
        CONVERT(date,c.startdate) as currentDate, 
        DATEDIFF(minute,c.startdate,c.enddate)+1 as minutesCurrentDay
        --1 due to the timeshifting to get the days in line
    FROM cte as c
    UNION ALL
    SELECT t.id, t.startdate, t.enddate, CONVERT(date, t.startdate) as currentDate, 
        DATEDIFF(minute,t.startdate, t.enddate) as minutesCurrentDay
    FROM #timing as t
    WHERE CONVERT(date,t.startdate) = CONVERT(date,t.enddate)
) as data
ORDER BY data.id, data.currentDate

-- Cleanup
DROP TABLE #timing

I've included demo code and a demo table structure as well. The point is just on the startdate and the enddate columns. You need to adjust it to your needed table structure. But that won't be to hard to add just a few columns without logic. :-)

Here is the demo input:

id          startdate               enddate
----------- ----------------------- -----------------------
1           2015-06-19 12:55:32.313 2015-06-20 13:05:32.313
2           2015-06-20 11:45:32.313 2015-06-20 12:55:32.313
3           2015-06-17 12:55:32.313 2015-06-20 12:55:32.313

And this is the result of the query:

id          startdate               enddate                 currentDate minutesCurrentDay
----------- ----------------------- ----------------------- ----------- -----------------
1           2015-06-19 13:03:35.887 2015-06-20 13:13:35.887 2015-06-19  657
1           2015-06-19 13:03:35.887 2015-06-20 13:13:35.887 2015-06-20  794
2           2015-06-20 11:53:35.887 2015-06-20 13:03:35.887 2015-06-20  70
3           2015-06-17 13:03:35.887 2015-06-20 13:03:35.887 2015-06-17  657
3           2015-06-17 13:03:35.887 2015-06-20 13:03:35.887 2015-06-18  1440
3           2015-06-17 13:03:35.887 2015-06-20 13:03:35.887 2015-06-19  1440
3           2015-06-17 13:03:35.887 2015-06-20 13:03:35.887 2015-06-20  784

Btw. the ORDER BY in the result around the subquery isn't needed if you won't the result in an ordered state.

Answer 2

So something like this?

declare @start date, @end date
set @start = '20150616'
set @end = dateadd(day, 1, @start)

SELECT 
    Name, State,
    datediff(second,
      case when StartDate < @start then @start else StartDate end,
      case when EndDate > @end then @end else EndDate end) / 60.0 as Duration
FROM 
    [emc].[dbo].[TMB_MachineStateReport]
WHERE 
    EndDate > @start 
    StartDate < @end

This takes everything where the range overlaps with the given day and calculates the time either from the start / end of the row or start / end of the day, depending on which one is on the day of question.

Didn't test this so hopefully it works.