Solución (1): la idea es consultar primero la ID duplicada y tomar el valor mínimo
select min(Id) Id,Email from Person group by Email
O
Select min(Id) as Id,distinct Email from Person
Luego elimine el valor que no está en esta ID
delete from Person where Id not in(select Id from ( select min(Id) Id,Email from Person group by Email)t)
Solución (2): utilice la consulta para descubrir que la ID de correo electrónico no es la más pequeña
select B.Id as Id from Person as A,Person as B where A.Id<B.Id and A.Email=B.Email
Luego elimine los resultados de la consulta
delete from Person where Id in(select Id from(select B.Id as Id from Person as A,Person as B where A.Id<B.Id and A.Email=B.Email) t)
