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

x
?
Solved

How to measure time since midnight in SQL query

Posted on 2013-01-16
4
Medium Priority
?
1,433 Views
Last Modified: 2013-01-16
We have simple problem.
A MS SQL stored procedure will be executed any day arround 1:0am (+/- 10 minutes). The stored procedure will perform simple math and statistic on data from particular table. For simplicity let us assume that it will calculate average value of record accumulated in a table.
The average value will be calculated for data in predetermined time frame : from 0:01am till 24:59pm for the previous day (in essence average for this values for yesterday).
Since we do not know when exactly the SQL query will run, we do not know the time different between midnight and the time when the SQL query runs.

The questions is: how can we refer to yesterday day as start time and end time?
My existing query is:

SET NOCOUNT ON
DECLARE @StartDate DateTime
DECLARE @EndDate DateTime
SET @StartDate = DateAdd(hh,-24,GetDate())
SET @EndDate = GetDate()

After this line the query continues with actual data extraction and manipulation - finding average.

The @StartDate is already set to Midnight at two days ago ( the midnight before the last one). The @EndDate shall be the time of the most recent Midnight.

Question: how do we set the @EndDate to be the time of the most recent Midnight??
0
Comment
Question by:uripapuk
  • 2
  • 2
4 Comments
 
LVL 23

Expert Comment

by:Steve Wales
ID: 38784615
Most recent midnight:

declare @EndDate datetime
set @EndDate = dateadd(dd, datediff(dd, 0, getdate())+0, 0)

If you want 23:59:59 of the one second before that you can subtract a second:

set @EndDate = dateadd(ss, -1, @EndDate)
0
 

Author Comment

by:uripapuk
ID: 38784679
This solution seems to be correct.
I have one clarifying question.

Since my statement is "SET @StartDate = DateAdd(hh,-24,GetDate())" does this means that am extracting only the date portion of the date OR does this means that I am only making a time shift in units of hours from the precise current time (mm,dd,yy) ??

What I like to make sure is that my EndDate is most recent midnight with precision up to 1 second AND my StartDate is the time of the midnight before the last one (midnight a day ago) with precision up to 1 second.

Would you please clarify.
0
 
LVL 23

Accepted Solution

by:
Steve Wales earned 1600 total points
ID: 38784729
What you're doing is substracting 24 hours from the current date/time with your statement.

If it runs at 01:05:00 AM, then you get 24 hours less than that.

If you want from mm/dd/yy 00:00:00 to mm/dd/yy 23:59:59 then you want to use something like this:

Your start date, if you want Midnight of 2 days ago:

 -- Yesterday at midnight (start of day)
SELECT @Start = dateadd(dd, datediff(dd, 0, dateadd(dd, -1, getdate()))+0, 0)

Open in new window

Then you want this for 23:59:59 last night:

set @EndDate = dateadd(dd, datediff(dd, 0, getdate())+0, 0)
set @EndDate = dateadd(ss, -1, @EndDate)

Open in new window

0
 

Author Closing Comment

by:uripapuk
ID: 38785050
The expert responded promptly and in detail on all questions asked. The solution proposed was tested and confirmed working as required.
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

I have written a PowerShell script to "walk" the security structure of each SQL instance to find:         Each Login (Windows or SQL)             * Its Server Roles             * Every database to which the login is mapped             * The associated "Database User" for this …
After restoring a Microsoft SQL Server database (.bak) from backup or attaching .mdf file, you may run into "Error '15023' User or role already exists in the current database" when you use the "User Mapping" SQL Management Studio functionality to al…
Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an anti-spam), the admin…
How can you see what you are working on when you want to see it while you to save a copy? Add a "Save As" icon to the Quick Access Toolbar, or QAT. That way, when you save a copy of a query, form, report, or other object you are modifying, you…

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