How do I add required characters to a random password?

Question

SQL

await queryRunner.query(`CREATE OR REPLACE FUNCTION random_hex(int) RETURNS TEXT as $$
            SELECT string_agg(substring('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!#$%&()*+,-./:;<=>[email protected][]^', ceil(random() * 85)::integer, 1), '') FROM generate_series(1, $1);
        $$ language sql;`);