[AccessD] Nz trap with dates in queries

Stuart McLachlan stuart at lexacorp.com.pg
Fri May 3 03:59:47 CDT 2013


It implicitly castes as a number with no problems.

I frequently use  things like:
TotalCharge: Cost * Qty  + NZ(FreightCharge,0)


On 2 May 2013 at 10:14, Charlotte Foust wrote:

> That issue has been around forever, Gustav.  Nz always needs to be cast
> into a datatype unless you're looking for a string.
> 
> Charlotte
> 
> On Thu, May 2, 2013 at 12:08 AM, Gustav Brock <gustav at cactus.dk> wrote:
> 
> > Hi all
> >
> > I browsed this article:
> >
> > http://www.fmsinc.com/MicrosoftAccess/query/sort/multiple-dates.htm
> >
> > and much to my surprise the note about the Nz trap is true.
> >
> > When used in a query, this expression returns a string:
> >
> >     DateNotNull: Nz([DateFieldWithNulls], Date())
> >
> > You can easily see it, because if you apply a date format to the column, it
> > has no effect.
> >
> > The real strange part, however, is that if you add two other columns:
> >
> >     TypeDate: VarType([DateFieldWithNulls])
> >     TypeDatez: VarType(Nz([DateFieldWithNulls], Date()))
> >
> > the first returns 7 (DateTime) and 1 (Null) while the other returns 7s only
> > ... no 8s for string!
> >
> > The workaround is either of these methods - the first corrects the result,
> > the second (from the article) uses a good, old alternative:
> >
> >     DateNotNull: CDate(Nz([DateFieldWithNulls], Date()))
> >     DateNotNull: IIf([DateFieldWithNulls] Is Null, Date(),
> > [DateFieldWithNulls])
> >
> > /gustav
> >
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> >
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