Robin-
A Null is an "unknown" value. Any comparison on a Null will always be false
(both = and <>). Any arithmetic expression that includes a Null will always
yield a Null. If you concatenate ( & operator ) a Null with another string, the
result is the other string. If you concatenate ( + operator ) a Null with
another string, the result is Null.
A Zero Length String is a known value. It is a string that has no characters in
it. If you compare two ZLS for equality, the result will be TRUE. If you check
to see if a string containing data is greater than a ZLS, the answer will be
TRUE.
Does that help?
John Viescas, author
Microsoft Office Access 2010 Inside Out
Microsoft Office Access 2007 Inside Out
Building Microsoft Access Applications
Microsoft Office Access 2003 Inside Out
SQL Queries for Mere Mortals
http://www.viescas.com/
(Paris, France)
-----Original Message-----
From: MS_Access_Professionals@yahoogroups.com
[mailto:MS_Access_Professionals@yahoogroups.com] On Behalf Of Robin Chapple
Sent: Thursday, August 25, 2011 7:54 AM
To: MS_Access_Professionals@yahoogroups.com
Subject: RE: [MS_AccessPros] Spare bracket problem
Thanks for the advice.
This project is for a branch of our organisation and we only meet
once each week. I will progress at our next meeting.
In the meantime where do I learn the difference between "zero length"
and "null' and how either was implied in the code.
Many thanks,
Robin
At 22/08/2011 08:49 PM, you wrote:
>.. but that also begs the question why Robin needs a zero-length
>string instead
>of a null.
>
>John
>
>-----Original Message-----
>From: MS_Access_Professionals@yahoogroups.com
>[mailto:MS_Access_Professionals@yahoogroups.com] On Behalf Of John Viescas
>Sent: Monday, August 22, 2011 12:25 PM
>To: MS_Access_Professionals@yahoogroups.com
>Subject: RE: [MS_AccessPros] Spare bracket problem
>
>Graham-
>
>Duh. My face is RED! <s>
>
>
>John Viescas, author
>Microsoft Office Access 2010 Inside Out
>Microsoft Office Access 2007 Inside Out
>Building Microsoft Access Applications
>Microsoft Office Access 2003 Inside Out
>SQL Queries for Mere Mortals
>http://www.viescas.com/
>(Paris, France)
>
>
>
>-----Original Message-----
>From: MS_Access_Professionals@yahoogroups.com
>[mailto:MS_Access_Professionals@yahoogroups.com] On Behalf Of Graham Mandeno
>Sent: Monday, August 22, 2011 12:13 PM
>To: MS_Access_Professionals@yahoogroups.com
>Subject: RE: [MS_AccessPros] Spare bracket problem
>
>Hi Robin
>
>
>
>Are you sure you copied and pasted the exact expression? It looks fine - 2
>opening and 2 closing parentheses, and the square brackets match too.
>
>
>
>I agree with John that there are simpler ways to do this, but [ParterName] +
>"" won't cut the mustard because if [ParterName] is Null then the result
>will be Null.
>
>
>
>Instead, try [PartnerName] & ""
>
>
>
>Best regards,
>
>Graham
>
>
>
>From: MS_Access_Professionals@yahoogroups.com
>[mailto:MS_Access_Professionals@yahoogroups.com] On Behalf Of Robin Chapple
>Sent: Monday, 22 August 2011 18:02
>To: MS_Access_Professionals@yahoogroups.com
>Subject: [MS_AccessPros] Spare bracket problem
>
>
>
>
>
>I am using this code in a query:
>
>IIf(IsNull([Partnername]), "", [Partnername])
>
>and an error message complains that I have too many curved brackets.
>
>What have I missed?
>
>Many thanks,
>
>Robin Chapple
>
>
>
>
>
>[Non-text portions of this message have been removed]
>
>
>
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