Let’s say you have a table called person:

CREATE TABLE person (
    person_id BIGINT NOT NULL,
    last_name VARCHAR(255) NOT NULL,
    first_name VARCHAR(255),
    age INT NOT NULL,
    PRIMARY KEY (person_id)
);

You can create a new table of people over 30 like this:

CREATE TABLE people_over_30 AS SELECT * FROM person WHERE age > 30;