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MySQL Finding Duplicates in a Normalized Database

Jacob Leis
Jacob Leis asked
on
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Last Modified: 2017-03-28
I need to find duplicate records based on the following query:

SELECT  p.id, p.first, p.last, a.address1, a.city, a.postalcode1
FROM 	global_main.person p,
		global_main.person_address pa,
		global_main.address a
WHERE 	p.id = pa.person_id
AND     a.id = pa.address_id

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Obviously the id will be unique for each record.  What would constitute a duplicate would be matching data in the following columns:
- p.first
- p.last
- a.address1
- a.city
- a.postalcode1

I've never done joins across tables to determine duplication for a query such as this.  What I would need returned would be a list of the lowest id column value for each duplicate instance.  There are cases where there are multiple 'duplicates'.  Any help will be greatly appreciated.  Thank you.
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