DISTINCT funtion

[Tom Wickerath]

A Union query is considered a read-only recordset.

Suppose you were Mr. JET DB Engine, and your user wanted to add a new record
to a union query that you dutifully produced. The next thing you'd be asking
is which table do you want me to add this record to? Considering that a
union query can be based on 1 to n tables, where n is some fairly large
number (I'm not even going to guess), you'd need some way to identify exactly
which table, of those n tables selected, that you wanted the record added to.
That doesn't seem all that practicle, does it?


Tom Wickerath
Microsoft Access MVP

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[John Spencer]

Plus if you don't use UNION ALL the records have been "combined" so that
one record could represent multiple records in the same table. Again,
which one of the many records should be updated.

IF you explain why you think you need to update a record, perhaps
someone can come up with a solution for you. It would involve VBA code
and changing the union query to specify the table name PLUS either all
fields would need to be named the same in all the tables or there would
have to be another way to identify the fields.

In other words, it isn't very practical to use a UNION query for
anything other than displaying data in a report or for displaying data
on a form.