postgresHow to filter resulting set after grouping is done

SELECT first_name, COUNT(*) AS count FROM person GROUP BY first_name HAVING count >= 2;ctrl + cgithub

`first_name, COUNT(*) AS count` select the column `first_name` and apply an aggregate function named `COUNT()` on every row from all columns that counts the number of rows and name this column `count`	`GROUP BY first_name` group the result set by `first_name`
`HAVING count >= 2` return only the rows that have 2 or more occurrences of the same `first_name`