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

For postgresql:

SELECT * AS rec 
FROM (
    SELECT lastname, COUNT(*) AS counter 
    FROM students 
    GROUP BY lastname) AS tbl 
WHERE counter > 1;