Re: No success with setting query criteria for returning empty
- From: "Allen Browne" <AllenBrowne@xxxxxxxxxxxxxx>
- Date: Tue, 18 Oct 2005 10:32:14 +0800
If there is nothing at all in the Status field for active students, the
value will be Null
In the Criteria row under this field in query design, enter:
Is Null
Nulls behave differently than other types of data. A null really means
'Unknown', or 'Not applicable'. Strictly, it is not the right thing to store
where the student's status is known. It would make more sense to use an
Update query to change all the nulls into another code such as "C" for
Current students. (If it's somebody else's application, that might break the
way they set up the rest of the application though.)
If you are interesting in learning about how to handle Nulls, see:
Common errors with Null
at:
http://allenbrowne.com/casu-12.html
--
Allen Browne - Microsoft MVP. Perth, Western Australia.
Tips for Access users - http://allenbrowne.com/tips.html
Reply to group, rather than allenbrowne at mvps dot org.
"RC" <RC@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:05EBA8C3-D362-4C53-BC62-07E64A81FDD2@xxxxxxxxxxxxxxxx
>I have imported tables from another database into Access and one of these
> tables has a field that stores a value that denotes the status for each
> student enrolled in a school. The values appear as "N" for students "Not
> Returning" for a new school term, "I" for students withdrawing during the
> term and are "Inactive" for the remainder of the term, and what appears to
> be
> as "blanks" or "empty" for "active" students. Using a query on that table.
> I'm trying to set the criteria for the Status field so that it will return
> only "active" students, but having no success with trying conditions such
> as
> Not Like "N" And Not Like "I", or <> "I" And <> "N", or Like " ", or = "
> ".
> Each of these appear to return no data at all.
> The query runs fine when setting the criteria of the Status field as
> either
> Like "N" to return only the students "Not Returning", Like "I" to return
> only students withdrawing during the term, or Like "I" or Like "N" to
> return
> all the student who are not active. It's only when setting the criteria so
> that only "active" students are returned by the query that does not seem
> to
> work.
> I'm wondering if the Status field of the imported table could have some
> hidden value for the "active" students, and Access can "see" this value.
> The
> Status field appears as being "blank" or empty for "active" students in
> its
> original database as well. All help will be greatly appreciated.
> Thanks in advance,
> RC
.
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