I am still learning how to use self-joins.
I would like to find out if somebody has multiple accounts by querying the same id. My understanding of self join is the following:
select,
a.account_number,
a.person_id,
b.person_id
from table a
inner join table b
on a.person_id = b.person_id
But it is bringing back the person_id twice but not showing me if there are different accounts.
Can I have some guidance please?
Many Thanks, JB
