Solved

Date format in SQL query string

Posted on 2014-12-14
10
244 Views
Last Modified: 2014-12-27
I have a slight problem with date formating.

I want to lookup a vb,net date in an SQL table and i keep getting errors, the first part of teh code (SET) is fine, the issue is the StartDate and CycleStart which are both dates.  

SQL.RunQuery("UPDATE temptbl_Stops SET DowntimeCode = '" & dc & "' WHERE StartDate =  & CycleStart &  ")

Any help most welcome.
0
Comment
Question by:SweetingA
  • 4
  • 3
  • 2
  • +1
10 Comments
 
LVL 18

Expert Comment

by:SimonAdept
ID: 40498640
Pass the date as a string, formatted as yyyymmdd (a language-neutral literal).

SQL.RunQuery("UPDATE temptbl_Stops SET DowntimeCode = '" & dc & "' WHERE StartDate = '"  & format(CycleStart,"yyyymmdd") &  "'")
0
 

Author Comment

by:SweetingA
ID: 40498665
Does not error now but still yields no result

Datetime shown Vb is #1/26/2014 3:02:50 PM# and teh date i need to compare to in SQL is 2014-09-13 15:04:50.000.

Thanks for the help so far.
0
 
LVL 18

Expert Comment

by:SimonAdept
ID: 40498765
Ah, you're comparing datetimes rather than dates. The two datetimes you want to compare are not identical. Was that deliberate or a typo?

If you want to get a datetime within a one day range...
SQL.RunQuery("UPDATE temptbl_Stops SET DowntimeCode = '" & dc & "' WHERE StartDate between '"  & format(CycleStart,"yyyymmdd") &  "' AND  Dateadd(dd,1,'" &  format(CycleStart,"yyyymmdd") & "')")

if you want the exact comparison, I think you want this
SQL.RunQuery("UPDATE temptbl_Stops SET DowntimeCode = '" & dc & "' WHERE StartDate = '"  & format(CycleStart,"yyyymmdd hh:mm:ss") &  ":000'")
0
 
LVL 11

Expert Comment

by:LordWabbit
ID: 40498766
I agree with SimonAdept, in that using an ISO standard date of yyyy-mm-dd should resolve all date issues, the fact that you are not getting any results probably means that the date is not being stored as a datatype of datetime in the database, but is probably being stored as a varchar.  

Also never use inline SQL, EVER!  It is one of the most common forms of attack on the internet (SQL Injection)

Even if it is an internal intranet site it's a bad habit and should never be used, use parameters instead and if you absolutely have to continue using inline SQL at least sanitize your inputs.

If the datetime is stored as varchar casting it to a datetime could resolve your problems
SQL.RunQuery("UPDATE temptbl_Stops SET DowntimeCode = '" & dc & "' WHERE CAST(StartDate AS DATETIME) = '"  & format(CycleStart,"yyyymmdd") &  "'")

Open in new window


This will not work if all of the StartDate's are not valid datetime values.
0
 

Author Comment

by:SweetingA
ID: 40498873
Datestime is stored as datetime not varchar
0
How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

 

Author Comment

by:SweetingA
ID: 40498884
I have tried several different formats including adding - between year/m/d but makes no difference, no errors but does nothing
0
 
LVL 11

Expert Comment

by:LordWabbit
ID: 40499045
Well to test perhaps run the statement directly against the database.  Is there a rollback in place?  Are you seeing a "records affected count" more than once, which is signs of a trigger changing your update?
0
 

Author Comment

by:SweetingA
ID: 40499141
Looks like you can only reformat a datetime to a string and not to a date time, once this is done no direct comparison can be made.

An sql count statement works only if i type in the dtae, if i type in the variable it returns nothing.

I am very much a novice so you will have to be patient.
0
 
LVL 18

Accepted Solution

by:
SimonAdept earned 500 total points
ID: 40499262
A sql select count(*) query is a good way to test... as you have done. Yes, the format() function returns a string, but if it's recognisable as a date, SQL Server will treat it as one, though not always the date you expect.
If you're getting no results from your count(*), try the > operator instead of the = operator and return a list of matching values rather than just a count. This might illustrate the reason for the unexpected result.
Do you have access to the design of the table you're querying? Can you check which datatype the column is?
Note that there are six possible date/time datatypes in MSSQL 2008:

Even yyyy-mm-dd is not foolproof for the datetime and smalldatetime datatypes. See this blog post among others. On my own system it gets interpreted as yyyy-dd-mm, unless I use the full ISO spec:
YYYY-MM-DDThh:nn[:ss[:mmm]]
0
 
LVL 48

Expert Comment

by:PortletPaul
ID: 40499663
Does not error now but still yields no result

Datetime shown Vb is #1/26/2014 3:02:50 PM# and teh date i need to compare to in SQL is 2014-09-13 15:04:50.000.

#1/26/2014 3:02:50 PM# can never equal 2014-09-13 15:04:50.000 no matter what formats you use; they just are not equal.

1/26/2014 is: 2014-01-26 ; and  2014-01-26 <> 2014-09-13 ; plus the times don't match either.

Please provide some sample data and the expected result. Make sure datetime values contain as much precision as possible.

Remember the precision of datetime is something like 3.5 milliseconds (from memory) so getting 2 datetime values  that are equal can be like trying to split an arrow that hit the bullseye.
0

Featured Post

How to run any project with ease

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

Join & Write a Comment

Hi all, It is important and often overlooked to understand “Database properties”. Often we see questions about "log files" or "where is the database" and one of the easiest ways to get general information about your database is to use “Database p…
In this article I will describe the Copy Database Wizard method as one possible migration process and I will add the extra tasks needed for an upgrade when and where is applied so it will cover all.
In this seventh video of the Xpdf series, we discuss and demonstrate the PDFfonts utility, which lists all the fonts used in a PDF file. It does this via a command line interface, making it suitable for use in programs, scripts, batch files — any pl…
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.

708 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

Need Help in Real-Time?

Connect with top rated Experts

16 Experts available now in Live!

Get 1:1 Help Now