SQL Query To Obtain Value that Occurs more than once

Question

I need to query my database to show the records inside my table where lastname occurs more than three times. Example: in my Students Table, there are 3 people with Lastname

Answer 1

I think this answer can also work (it may require a little bit of modification though) :

SELECT * FROM Students AS S1 WHERE EXISTS(SELECT Lastname, count(*) FROM Students AS S2 GROUP BY Lastname HAVING COUNT(*) > 3 WHERE S2.Lastname = S1.Lastname)