from employees
aggregate by:[emp_no] [
  emp_salary: average salary          # avg_salary should resolve to "AVG(salary)" (from stdlib)
]
join titles [emp_no]
aggregate by:[title] [
  avg_salary: average emp_salary
]
select salary_k: avg_salary / 1000    # avg_salary should resolve to "AVG(emp_salary)"
take 10                               # induces new SELECT
derive salary: salary_k * 1000        # salary_k should not resolve to "avg_salary / 1000"