SQL how to merge similar records into single row from same table?

Question

I'm currently trying to clean up a database of mailing subscribers that a former employee created. I've been able to consolidate and fix most issues (primarily duplicates), but I have instances of subscribers with duplicate records because they are subscribed to multiple regions. What I want to do is merge those duplicate records into 1.

Here is an redacted actual example of a duplicate record that I'd like to merge:

id     first     last    address    truck    machinery    gl    ne    nw
------------------------------------------------------------------------
1      Chuck     G....   12 Lorem   1                     1
2      Chuck     G....   12 Lorem            1                        1
3      Chuck     G....   12 Lorem            1                  1

And I'd like to merge the 2 into 1 record, and delete all duplicates (some have up to 9 duplicates) like this:

id     first     last    address    truck    machinery    gl    ne    nw
------------------------------------------------------------------------
1      Chuck     G....   12 Lorem   1        1            1     1     1

Answer 1

Use Group By and Max/Min Aggregate

SELECT id, 
       first, 
       last, 
       address, 
       Max(truck)     AS truck, 
       Max(machinery) AS machinery, 
       Max(gl)        AS gl, 
       Max(ne)        AS ne, 
       Max(nw)        AS nw 
FROM   yourtable 
GROUP  BY id, 
          first, 
          last, 
          address