Leetcode Delete Duplicate Emails problem solution

In this Leetcode Delete Duplicate Emails problem solution we need to write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id.

First Problem solution.

delete from Person
where Id in (select r.Id from  
             (select Id, row_number() over(partition by Email 
                                          order by Id
                                         ) as rk
             from Person) r
            where r.rk > 1
            );

Second Problem solution.

DELETE b
FROM Person a, Person b
WHERE a.Email = b.Email
AND a.Id < b.Id;

Third Problem solution.

delete from Person
where Id not in
(select mid from (select min(Id) as mid from Person
group by Email)T )