You'll need to use two separate queries. One to append data from the "main
table" in the main form, and the other to append data from the
subdatasheet's table.

It sounds like your use of Access nomenclature may be inaccurate and
that you might be simply using tables to interact with the data..

You should be using Forms and Queries to interact with the data and
never let your users even *see* the tables.

Please post back with a more complete description of what you're
trying to accomplish in the real world and how you're going about it.
Please include a description of your tables including their fields and
datatypes.

There are a couple other Access newsgroups that you might also find
instructive:

   microsoft.public.access.gettingstarted
   microsoft.public.access.tables design

There's a great resource for Access developers at

   www.mvps.org/access