[AccessD] Nz trap with dates in queries

Gustav Brock gustav at cactus.dk
Thu May 2 02:08:54 CDT 2013


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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