S.E. wrote:

I get a "type mismatch in expression" when saving a query. Why do I get this
and how do I correct this? My suspicion is my customerID and barcode fields
are not both autonumbers or the same type to relate but under the
relationships they join up.

What are the types of the fields in the table and what does
the query's SQL view look like?

If one is Text and the other is a number type, then use a
convesion function (CStr, CLng or ??).

--
Marsh
MVP [MS Access]