Working with avg, to_char, and having

Question

Display the department ID, average salary (in currency format), and the number of job IDs for each department. Limit the results to only those departments with more than 5 job IDs.

What I've tried so far.

select department_id, to_char(avg(salary, '$999,999.00')), count(job_id) from employees group by department_id, salary, job_id having SUM(job_id) > '5';

I'm having trouble understand what it means by "invalid number of arguments."

Answer 1

Only department_id should be appearing in the GROUP BY clause since you want to aggregate over departments, and not anything else.

SELECT department_id,
       CONCAT('$', FORMAT(AVG(salary), 2)) AS avg_salary,
       COUNT(*) AS num_job_ids
FROM employees
GROUP BY department_id
HAVING COUNT(*) > 5

I assumed in my answer that every job_id in the table is unique. If this is not the case, and you wanted to instead count/report unique jobs, then you can replace COUNT(*) with COUNT(DISTINCT job_id) .