title: Query identifying duplicate records with different values
body: <p>I have a table in which I have loaded records from 4 different sources.  There is no common factor between the records from each source except for FName, LName, Addr1, Addr2, City, State and Zip.  Each record is assigned a FileID by me based upon which source file they were loaded from.  I need to construct a query in which I can identify which person/household was found to be in all 4 files, 3 files, 2 files, etc.  I only need to maintain one record for each duplicate person/household.</p>
  
  <p>The other tricky part is that I have email address on 2 of the 4 files and also an Emailable field field that is coming in on the other two files.  This is a factor which I need to consider also when maintaining the single selected record.  </p>
  
  <p>For example, one group will be indicated by: “individuals who are in all of the following lists: DMA , Vehicle Ownership  and Lifestyle (Wealth Engine) lists. These individuals must have an email address.” But then another group needs to be identified as “individuals who are in all of the following lists: DMA , Vehicle Ownership  and Lifestyle (Wealth Engine) lists. These individuals DO NOT have an email address”</p>
  
  <p>Example Data:</p>
  
  <pre><code> ID                         FirstName LastName  FullName   Address1 Address2  City    State Zip     Zip4    EmailAddress            FILE    EMAILABLE
   06925901SNDCR44110G6520  S Nylah     Watson    NULL       1234 Main    NULL Anytown    ST  10000   2000    NULL                    DMA     Y
   1641189779                 Nylah     Watson    NULL       1234 Main         Anytown    ST  10000   2000    nylahwatson@gmail.com   LST 
   06925901SNDCR44110G6520  S Nylah     Watson    NULL       1234 Main    NULL Anytown    ST  10000   2000    NULL                    VEH     Y
   374977111                  Nylah     Watson    NULL       1234 Main    NULL Anytown    ST  10000   2000    nylahwatson@gmail.com   V12     NULL
   48770181SBRNT 1345M6352  S Watson    Nylah     NULL       4321 Main    NULL HOUSTON    TX  20000   3000    NULL                    DMA     N
   48770181SBRNT 1345M6352  S Watson    Nylah     NULL       4321 Main    NULL HOUSTON    TX  20000   3000    NULL                    VEH     N
   1933990731                 Watson    Nylah     NULL       4321 Main         Houston    TX  20000   3000                            LST 
  </code></pre>