text: Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
  ### Context:
  CREATE TABLE EMPLOYEE (EmployeeId VARCHAR); CREATE TABLE CUSTOMER (LastName VARCHAR, SupportRepId VARCHAR)
  ### Question:
  Please show the employee last names that serves no more than 20 customers.
  ### Answer:
  SELECT T1.LastName FROM CUSTOMER AS T1 JOIN EMPLOYEE AS T2 ON T1.SupportRepId = T2.EmployeeId GROUP BY T1.SupportRepId HAVING COUNT(*) <= 20