Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
?
Solved

how to sum total hours from date-time field in sql

Posted on 2015-02-19
9
Medium Priority
?
148 Views
Last Modified: 2015-02-20
I am trying to sum total hours that someone was sleeping from date-time field.  For example,  if a person sleeps at 1:00 am and wakes up on 5:00 am then i want to show that person slept for 4 hours as total hours of sleep from 1 to 5 am.  I want to extract the hour and the minutes from the date-field.  Here is how it look like my date-field
2015-02-19 00:00:00.000
2015-02-19 00:30:00.000
2015-02-19 01:00:00.000
2015-02-19 01:30:00.000
2015-02-19 02:00:00.000
2015-02-19 02:30:00.000
2015-02-19 03:00:00.000

Open in new window

This is from 12:00 AM to 3:00 AM so i would expect the total to be 3 Hours.  
I tried this but not working..
select  datepart(hour, cast(FullDatetime as time)) as totHours
from myTable
where id in (1, 2, 3,4,5, 7)

Open in new window

0
Comment
Question by:moe57
  • 5
  • 4
9 Comments
 
LVL 66

Expert Comment

by:Jim Horn
ID: 40619686
Really not following this, but if you're asking for a way to calculate the difference in times between the min and max of a given set, then copy-paste the below into your SSMS, execute to verify it works, then modify to meet your needs
CREATE TABLE #tmp (tm datetime) 

INSERT INTO #tmp (tm) 
VALUES 
('2015-02-19 00:00:00.000'), 
('2015-02-19 00:30:00.000'), 
('2015-02-19 01:00:00.000'), 
('2015-02-19 01:30:00.000'), 
('2015-02-19 02:00:00.000'), 
('2015-02-19 02:30:00.000'), 
('2015-02-19 03:00:00.000')

SELECT DATEDIFF(minute, Min(tm), Max(tm))
FROM #tmp
-- WHERE <whatever>

Open in new window

0
 
LVL 66

Accepted Solution

by:
Jim Horn earned 2000 total points
ID: 40619690
To return hours, with the decimal places to make sure 2.75 doesn't get cut off to 2 ...
SELECT DATEDIFF(minute, Min(tm), Max(tm)) / 60.0 as hours
FROM #tmp

Open in new window

0
 

Author Comment

by:moe57
ID: 40619716
Jim,  i have not looked at  your example yet but all what i need is somehow to sum total hours from the example i mentioned above.  The field has date and time so all what i need is to add up all the times and get the total number of hours which in this case is 3 hours.  I hope i am little bit clearer now.  thanks
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 66

Expert Comment

by:Jim Horn
ID: 40619727
Define for us at a Barney level of simplicity how the above set of datetime values adds up to three hours.
0
 

Author Comment

by:moe57
ID: 40619776
okay, i am happy to do that..
('2015-02-19 00:00:00.000'),  = 12:00 AM
('2015-02-19 00:30:00.000'),  = 12:30 AM
('2015-02-19 01:00:00.000'),  = 1:00 AM
('2015-02-19 01:30:00.000'),  = 1:30 AM
('2015-02-19 02:00:00.000'),  = 2:00 AM
('2015-02-19 02:30:00.000'),  = 2:30 AM
('2015-02-19 03:00:00.000')  =  3:00 AM
So when you add up from 12:00 am to 3:00 Am  total hours = 3 hours.  I am using military hours.  Thanks
0
 
LVL 66

Expert Comment

by:Jim Horn
ID: 40619780
That was provided to you in my first comment, where it takes the difference between the minimum and maximum values, then does a DATEDIFF to convert to minutes.  The second comments converts to hours with a decimal value.

If that's not what you need, explain again how the calculation is supposed to work.
0
 
LVL 66

Expert Comment

by:Jim Horn
ID: 40621300
I think where we may be tripping up here is the use of 'sum up', which implies summing all rows, i.e. midnight + 12:30 + 1 + 1:30 + 2 + 2:30 + 3 would equal 10:30.

I interpreted your question as the maximum value minus the minimum value.

If your definition of 'sum up' is different from the above two, spell it out in more clear language.
0
 

Author Comment

by:moe57
ID: 40622177
Jim, thanks for your help.  You did answer my question i just did not see your second answer where you were dividing 60.  Thanks
0
 

Author Closing Comment

by:moe57
ID: 40622179
thanks
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In this article we will learn how to fix  “Cannot install SQL Server 2014 Service Pack 2: Unable to install windows installer msi file” error ?
Recently we ran in to an issue while running some SQL jobs where we were trying to process the cubes.  We got an error saying failure stating 'NT SERVICE\SQLSERVERAGENT does not have access to Analysis Services. So this is a way to automate that wit…
Using examples as well as descriptions, and references to Books Online, show the different Recovery Models available in SQL Server and explain, as well as show how full, differential and transaction log backups are performed
Viewers will learn how to use the SELECT statement in SQL to return specific rows and columns, with various degrees of sorting and limits in place.
Suggested Courses

564 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question