Solved

'Simple' SQL Problem selecting null dates

Posted on 2009-05-06
4
445 Views
Last Modified: 2012-05-06
Hi,
This really should be simple, but I'm having strange behaviour on the following code:
This works fine (returns 31 rows):
DECLARE @numInstances int
EXEC      @numInstances = sp_executesql N'SELECT     COUNT(*) AS numInstances
FROM         xjrvw_TR_Instances
WHERE     (fkResponsiblePersonId = @ResponsiblePersonId) AND (fkOrganizationId = @OrganizationId) AND (TraceDate IS
NULL)',N'@ResponsiblePersonId int,@OrganizationId int',@ResponsiblePersonId=1,@OrganizationId=2

This returns 0 rows:
DECLARE @numInstances int
EXEC      @numInstances = sp_executesql N'SELECT     COUNT(*) AS numInstances
FROM         xjrvw_TR_Instances
WHERE     (fkResponsiblePersonId = @ResponsiblePersonId) AND (fkOrganizationId = @OrganizationId) AND (TraceDate IS
NULL)',N'@ResponsiblePersonId int,@OrganizationId int',@ResponsiblePersonId=1,@OrganizationId=2
GO
And this also returns 0 rows (from the SQL Profiler when I run through the app)
DECLARE @numInstances int
EXEC      @numInstances = sp_executesql N'SELECT     COUNT(*) AS numInstances
FROM         xjrvw_TR_Instances
WHERE     (fkResponsiblePersonId = @ResponsiblePersonId) AND (fkOrganizationId = @OrganizationId) AND (TraceDate IS
NULL)',N'@ResponsiblePersonId int,@OrganizationId int',@ResponsiblePersonId=1,@OrganizationId=2
GO

I have tried changing it to a store procedure, to no avail.  The problem is definitely with the TraceDate IS NULL  - it works without that part of the predicate. I tried TraceDate.ISNULL = 1 but it tells me 'Cannot call methods on datetime.'

Can anyone please help?  I need to run it through the app, which interprets the top code to the second version.  

Thanks!
Carol.

exec sp_executesql N'SELECT     COUNT(*) AS numInstances
FROM         xjrvw_TR_Instances
WHERE     (fkResponsiblePersonId = @ResponsiblePersonId) AND (fkOrganizationId = @OrganizationId) AND (TraceDate IS 
NULL)',N'@ResponsiblePersonId int,@OrganizationId int',@ResponsiblePersonId=1,@OrganizationId=2
GO
DECLARE @numInstances int
EXEC	@numInstances = sp_executesql N'SELECT     COUNT(*) AS numInstances
FROM         xjrvw_TR_Instances
WHERE     (fkResponsiblePersonId = @ResponsiblePersonId) AND (fkOrganizationId = @OrganizationId) AND (TraceDate IS 
NULL)',N'@ResponsiblePersonId int,@OrganizationId int',@ResponsiblePersonId=1,@OrganizationId=2
GO
DECLARE @ResponsiblePersonId int
SET @ResponsiblePersonId = 2
DECLARE @OrganizationId int
SET @OrganizationId=1
SELECT     COUNT(*) AS numInstances
FROM         xjrvw_TR_Instances
WHERE     (fkResponsiblePersonId = @ResponsiblePersonId) AND (fkOrganizationId = @OrganizationId) AND (TraceDate IS 
NULL)

Open in new window

0
Comment
Question by:jrepdev
  • 2
4 Comments
 
LVL 8

Expert Comment

by:vinurajr
ID: 24322582
try with isnull(TraceDate,1)=1 or TraceDate is null
0
 

Author Comment

by:jrepdev
ID: 24322712
Thanks.  Nice try, but that didn't work either...  It doesn't fail, just returns 0 rows instead of 31.  I could mention that this is being implemented via an .xsd using C#, not that it will help :-)

I appreciate your help,
Carol.
0
 
LVL 57

Accepted Solution

by:
Raja Jegan R earned 500 total points
ID: 24322938
I hope this issue is with respect to your ANSI_NULL settings in SQL Server 2005.

When SET ANSI_NULLS is ON, a SELECT statement that uses WHERE column_name = NULL returns zero rows even if there are null values in column_name. A SELECT statement that uses WHERE column_name <> NULL returns zero rows even if there are nonnull values in column_name.

When SET ANSI_NULLS is OFF, the Equals (=) and Not Equal To (<>) comparison operators do not follow the SQL-92 standard. A SELECT statement that uses WHERE column_name = NULL returns the rows that have null values in column_name. A SELECT statement that uses WHERE column_name <> NULL returns the rows that have nonnull values in the column. Also, a SELECT statement that uses WHERE column_name <> XYZ_value returns all rows that are not XYZ_value and that are not NULL.

Referred from http://msdn.microsoft.com/en-us/library/ms188048(SQL.90).aspx

If you have ANSI_NULLS ON, then use IS NULL in where condition
If you have ANSI_NULLS OFF, then use = NULL in where condition.
0
 

Author Closing Comment

by:jrepdev
ID: 31578853
Actually, my problem was much simpler - I'd transposed the values for the parameters!  However, that was a really interesting post - thank you - I didn't know that about Ansi Nulls.
0

Featured Post

Free Tool: ZipGrep

ZipGrep is a utility that can list and search zip (.war, .ear, .jar, etc) archives for text patterns, without the need to extract the archive's contents.

One of a set of tools we're offering as a way to say 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've encountered valid database schemas that do not have a primary key.  For example, I use LogParser from Microsoft to push IIS logs into a SQL database table for processing and analysis.  However, occasionally due to user error or a scheduled task…
So every once in a while at work I am asked to export data from one table and insert it into another on a different server.  I hate doing this.  There's so many different tables and data types.  Some column data needs quoted and some doesn't.  What …
With Secure Portal Encryption, the recipient is sent a link to their email address directing them to the email laundry delivery page. From there, the recipient will be required to enter a user name and password to enter the page. Once the recipient …
Attackers love to prey on accounts that have privileges. Reducing privileged accounts and protecting privileged accounts therefore is paramount. Users, groups, and service accounts need to be protected to help protect the entire Active Directory …

730 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