Need Advice On Best Way To Make Dbase Record Updates

Approximately once a month, a client of ours sends us a bunch of
comma-delimited text files which I have to clean up and then import
into their MS SQL database. All last week, I was using a Cold Fusion
script to upload the cleaned up files and then import the records they
contained into the database, though obviously, the process took
friggin' forever, and could have been done 500x quicker had I done it
directly on the server. My SQL knowledge is somewhat limited, however,
so I had no choice but to stick to what I know, which is Cold Fusion
programming.

In the process of cleaning up some of these comma-delimited text files,
I inadvertently messed up some of the 10-digit zip codes, by applying
the wrong Excel formula to the ZIP columns. These records were imported
into the database with obviously incorrect zip codes (ie: single
digit). So now, I have to find the best and quickest way possible to
compare these records in the database (that have the single digit zip
codes) with the unmodified data, and to update the zip codes with the
correct data.

I've had no luck setting up a TEXT file as an ODBC datasource, -- so
I've ruled that out completely. I've also managed to import the
unmodified data into an Access database, and to set it up as a Cold
Fusion datasource. But it seems this 2nd road I've been traveling down
is not the ideal approach either.

My question is, -- assuming that I'll be able to import the records
from the Access database into their own table on the SQL server, -- how
should I go about the process of updating these records that have the
incorrect zip codes?

Here is the specific logic I would need to employ:

* Here is a list of records, each of which contains an incorrect
1-digit zip code (Database A / Table A)

* Here is a much longer list of records (which contains all of the
records from Database A / Table A + thousands more), each of which
contains a correct 5-digit zip code (Database B / Table B)

* Compare both lists of records and run the following query/update:

When a record in Database A / Table A has matching "name", "address1",
and "address2" values as a record in Database B / Table B -- update the
record in Database B / Table B with the zip code from the matching
record in Database A / Table A.

Would anyone care to write a sample query for me that I could run
directly on the SQL server, or at least give me some pointers?

The specific field names are as follows:
name,address1,address2,city,state,zip

Thanks in advance!
- yvan