Michael,
You still haven't made it clear whether this problem is in Access or
Excel. Are you finding
(1) that apparently identical [Rep ID] values in the two tables are
being seen as different by Access,
(2) that Access sees the values as identical but Excel sees them as
different?
If (1), I don't think it's possible to have "invisible strings" in an
Access text field. Conceivably the source program included trailing
spaces or other invisible characters (tabs, linefeeds) in the data. You
can check that by running this query, replacing XXX with your actual
tablename.
SELECT [Rep ID], Len([Rep ID]) AS FieldLength FROM XXX;
(create a new query, switch it to SQL view, and paste in the above
string). Then run the query and observe whether the displayed length
matches the visible number of characters.
If you haven't already done so, create a query in Access that joins the
two tables on [Rep ID]. (Create a new query. Add both tables to it. Drag
the [Rep ID] field from one table to the other. Then drag the two RepID
fields and some others from the tables into the query design grid.) WHen
you run the query, do the records from the two tables line up right(i.e.
does the query correctly display values from corresponding records in
the two tables)? Are there any records missing?
If the records line up properly and there are no records missing, the
[Rep ID] values are OK and the problem is almost certainly in Excel, or
in whatever process you are using to export the data to Excel.
If the records don't line up, or some are missing, there's a problem
with the [Rep ID] values. Use the Find Unmatched query wizard to find
the duds.