Example SQL Query to find all the records with the maximum value

query.sql

select 
    oid, count(distinct pid)
from
    owns
group by oid
having count(distinct pid) >= (select 
        T.max
    from
        (select 
            oid, count(distinct pid) as max
        from
            owns
        group by oid
        order by max desc
        limit 1) as T)

relation.md

Relations

• Pet (pid, name, age, species, breed)
• Owner (oid, first_name, last_name, age, address, phone, email)
• Owns (pid, oid)
• Owns.pid is a foreign key that references Pet.pid
• Owns.oid is a foreign key that references Owner.oid