Solved

DATEADD Off By An Hour

Posted on 2014-09-18
4
197 Views
Last Modified: 2014-09-19
Hello:

One of the fields I have in a report is based on the following T-SQL query:

DATEADD(s,({*Document_tb:TimeCreated} + (3600*-5)),'1/1/1970')

The customer is saying that the resulting "Time Created" is off by an hour.  Specifically, this field displayed as 2:24 PM, when it should have displayed as 3:24 PM.

The customer is in the Eastern Time Zone.  It is possible, too, that this field is not changing with the Daylight Savings Time change occurring in the spring.  

Anyway, to manually fix this, do I change the -5 to a different number such as -4 or -6?

TBSupport
0
Comment
Question by:TBSupport
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
4 Comments
 
LVL 45

Accepted Solution

by:
Kent Olsen earned 500 total points
ID: 40331539
Hi TBSupport,

It looks like the code is converting from GMT to EST.  

Change -5 to -4.

And note that this kind of conversion may have other issues down the line....
0
 
LVL 34

Expert Comment

by:ste5an
ID: 40331542
First of all: get rid of the unnecessary calculus. Use DATEADD(HOUR,{},'') instead. Your time created value must be an integer value. So when this is a time value, then the problem maybe the implicit conversion from your time value to INT. Maybe DATEADD(HOUR, -5, {}) is sufficient.
0
 
LVL 69

Expert Comment

by:Scott Pletcher
ID: 40331630
>> It is possible, too, that this field is not changing with the Daylight Savings Time change occurring in the spring. <<

I strongly suspect that's it.  Nasty, because then you need a table for DST so you can tell if the setting is different now vs. when the document was created.  But I think you'll need that to accurately translate these times.
0
 
LVL 49

Expert Comment

by:PortletPaul
ID: 40331947
Appears that the field value is a Unix timestamp (expressed as seconds from 1970-01-01) hence the arithmetic requiring 3600*-5 :: and I don't believe there is an implicit conversion, just adding seconds to a date.

alternate: put time out with EST as suffix (i.e. don't attempt daylight saving conformance)

i.e.
this field displays as 2:24 PM EST

(and it won't display 3:24 PM ESST)

----
or whatever your summer time TZ abbreviation is
0

Featured Post

NFR key for Veeam Backup for Microsoft Office 365

Veeam is happy to provide a free NFR license (for 1 year, up to 10 users). This license allows for the non‑production use of Veeam Backup for Microsoft Office 365 in your home lab without any feature limitations.

Question has a verified solution.

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

Long way back, we had to take help from third party tools in order to encrypt and decrypt data.  Gradually Microsoft understood the need for this feature and started to implement it by building functionality into SQL Server. Finally, with SQL 2008, …
Data architecture is an important aspect in Software as a Service (SaaS) delivery model. This article is a study on the database of a single-tenant application that could be extended to support multiple tenants. The application is web-based develope…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…
Sometimes it takes a new vantage point, apart from our everyday security practices, to truly see our Active Directory (AD) vulnerabilities. We get used to implementing the same techniques and checking the same areas for a breach. This pattern can re…

628 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