Joe:

I don't have a great deal of information regarding your exact setup,
however, it appears that you could do an INNER JOIN between the two
"spreadsheets."  An Excel worksheet is limited to about 65536 rows, so I am
assuming your larger data matrix is already in Access.  You could link the
smaller data set which I am assuming is in Excel into Access and then
perform the INNER JOIN query.

You can link an Excel spreadsheet into Access through the File menu, Get
External Data, Link Tables option.  In the Files of Type drop down, select
Excel and browse to your workbook.  You can then create a query from the two
tables joining them on the appropriate field.

I'm trying to do the following in Excel but am having a really tough
time and am wondering if Access will do it....

I have  a database matrix with about a half million rows in it and
about a dozen columns.  I have another database with about 1000 rows in
it.  Each of these is a long number.  What I would like to do is sort
the huge matrix so it only selects/sorts rows that contain ones that
have the same values of the 1000 out of the other spreadsheet.  In
other words each row needs to look at the list of 1000 and say yes or
no to whether it contains one of the numbers.

Does this make sense?  Will Access do this?  How easy is it?

Thanks folks.

Joe