CTE to find duplicates? - sql

Question

Can someone show me how i would add to this CTE to include the column 'Address Type ' that is stored in another table called 'WeccoPartyAddress'?
I am trying to find duplicates for the first and last name, and mailing address where Address Type address = 'Mailing'
with dups as (
select
wp.GtId
from CORE.WeccoParty wp
where exists (select 1
from CORE.WeccoParty wpe
where wp.FirstName = wpe.FirstName
and wp.LastName = wpe.LastName
and wp.Dob = wpe.Dob
and wp.GtId <> wpe.GtId
)
)
select distinct
wp.GtId,
wp.CrmPartyId,
wp.LegalName,
wp.BusinessClass,
wp.RmFullName,
wp.PbeFullName,
wp.OverallClientStatus,
wp.OverallRpStatus,
wp.FirstName + ' ' + wp.LastName FullName,
wp.Dob
from CORE.WeccoParty wp
join dups d on d.GtId = wp.GtId
order by 9,1

Answer 1

Consider extending your CTE by adding a JOIN clause in outer and subquery to the WeccoPartyAddress table with needed WHERE clauses. Notice too the distinct added to avoid repeated IDs for possible one-to-many relationship between the tables.
with dups as (
select distinct p.GtId
from CORE.WeccoParty p
join CORE.WeccoPartyAddress a ON p.GtId = a.GtId
where exists (select 1
from CORE.WeccoParty sub_p
left join CORE.WeccoPartyAddress sub_a
on sub_p.GtId = sub_a.GtId and sub_a.AddressType = 'Mailing'
where (p.FirstName = sub_p.FirstName
and p.LastName = sub_p.LastName
and p.Dob = sub_p.Dob
and p.GtId <> sub_p.GtId)
and a.MailingAddress = sub_a.MailingAddress
and a.GtId <> sub_a.GtId
)
)
And depending on data and relationships (e.g., can GtId have same bio details AND/OR same mailing address?) which you would know more, you may need to adjust above query. These may involve swapping left join to join and/or the WHERE conditions such as:
where (p.FirstName = sub_p.FirstName
and p.LastName = sub_p.LastName
and p.Dob = sub_p.Dob
and p.GtId <> sub_p.GtId)
or
(a.MailingAddress = sub_a.MailingAddress
and a.GtId <> sub_a.GtId)