Please show the employee first names and ids of employees who serve at least 10 customers.
create table customer (firstname varchar, supportrepid varchar, PRIMARY KEY (firstname)); create table employee (employeeid varchar, PRIMARY KEY (employeeid))
select t1.firstname, t1.supportrepid from customer as t1 join employee as t2 on t1.supportrepid = t2.employeeid group by t1.supportrepid having count(*) >= 10