How do I create a query that uses multiple fields to do the linking between
tables when sometimes some of the values in one or two of the fields have
zero length values in them?  I cannot set a rule that will not allow zero
length because we are using a table from someone elses database and the data
already exists in the tables.  

Right now I have done some testing and if I eliminate the link between the
zero length fields the data shows up with the link in there, no data!

Thanks for you help.