Query identifying duplicate records with different values [closed] - sql

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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.
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.
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”
Example Data:
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

Answer 1

Depending on how many/how flexible the groups you need are, you may want to do something like this:
Select Name, Address... -- Fields you want to group on (consider to identify the same person)
, max(case when File = 'DMA' then 1 else 0 end) as HasDMAFile
, max(case when File = 'Veh' then 1 else 0 end) as HasVEHFile --repeat for your other file types
, max(case when emailaddress is not null then 1 else 0 end) as HasEmail
From MyTable
Group by Name, Address...--same list of fields as you use at the beginning of your select
Then use that result set to create your combination groups, for example:
; with CTE as (Query from Above)
Select *
, case when HasDMAFile = 1
and HasVEHFile = 1
and HasLSTFile = 1
and HasEmail = 0
then 'Group 1'
when HasDMAFile = 1
and HasVEHFile = 1
and HasLSTFile = 1
and HasEmail = 1
then 'Group 2' --etc for more groups here; make sure your groups are either mutually exclusive or in a logical order, since the case statement is evaluated in the order it's written
end as Grp
from CTE

Answer 2

SELECT
FName, LName, Addr1, Addr2, City, State, Zip,count(distinct File)
FROM <TABLE>
GROUP BY FName, LName, Addr1, Addr2, City, State, Zip
Having count(distinct File)=4
The emails could be coalesced, but you need to figure out an order of preference.