Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Problem with datediff in SQL not calculating correctly

Posted on 2014-03-11
3
Medium Priority
?
410 Views
Last Modified: 2014-05-05
SQL Code CAST(DATEDIFF(ss, StartDate, StopDate) AS Numeric(4 , 0))

Result

2014-01-26 15:01:00.000      2014-01-26 15:01:20.000      60
2014-01-26 15:04:50.000      2014-01-26 15:05:00.000      20

Expected

2014-01-26 15:01:00.000      2014-01-26 15:01:20.000      20
2014-01-26 15:04:50.000      2014-01-26 15:05:00.000      10

All ideas most welcome
0
Comment
Question by:SweetingA
3 Comments
 
LVL 21

Accepted Solution

by:
Dale Burrell earned 1500 total points
ID: 39922132
Thats pretty odd, what happens when you hardcode it i.e. run the query:

select datediff(ss, '2014-01-26 15:01:00.000','2014-01-26 15:01:20.000')

Open in new window


Also could you post your actual query as

select StartDate, EndDate, datediff(ss, StartDate, EndDate) from MyTableName
0
 
LVL 33

Expert Comment

by:knightEknight
ID: 39922135
My test code produces the desired results, so I'm not sure why you would be seeing a different result.  What are the column types of the start and stop date(s)?  Note that it would only take a few days difference between the two dates to overflow the numeric(4,0) field.

declare @StartDate datetime , @StopDate datetime

select @StartDate = '2014-01-26 15:01:00.000' , @StopDate = '2014-01-26 15:01:20.000'
select CAST(DATEDIFF(ss, @StartDate, @StopDate) AS Numeric(4,0))

select @StartDate = '2014-01-26 15:04:50.000' , @StopDate = '2014-01-26 15:05:00.000'
select CAST(DATEDIFF(ss, @StartDate, @StopDate) AS Numeric(4,0))

Open in new window

0
 
LVL 70

Expert Comment

by:Scott Pletcher
ID: 39927975
Hmm.  It looks like it had to be that the real difference was, say, 10020, which was then truncated to become 0020 in the final result.

But that would normally cause either an error or a NULL value, depending on your SQL settings.

Is it possible that the actual code and computations might have allowed the value to be truncated that way without causing an error?
0

Featured Post

[Webinar] Cloud Security

In this webinar you will learn:

-Why existing firewall and DMZ architectures are not suited for securing cloud applications
-How to make your enterprise “Cloud Ready”, and fix your aging DMZ architecture
-How to transform your enterprise and become a Cloud Enabler

Question has a verified solution.

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

In part one, we reviewed the prerequisites required for installing SQL Server vNext. In this part we will explore how to install Microsoft's SQL Server on Ubuntu 16.04.
What if you have to shut down the entire Citrix infrastructure for hardware maintenance, software upgrades or "the unknown"? I developed this plan for "the unknown" and hope that it helps you as well. This article explains how to properly shut down …
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
Via a live example, show how to extract insert data into a SQL Server database table using the Import/Export option and Bulk Insert.

916 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