Problem:
Question 1: Create a query that will return the average of the maximum employee salaries in each department. You will be gathering data from the employees table?
Question 2: Create a query that will display the employee_id and department_id from the employees table and a second query displaying employee_id, job_id, start_date, and department_id from the job_history table. You will combine the results as one single output. Make sure you suppress duplicates in the output.
Question 3: Create a query that will display an employee's department_id, manager_id, and job_id as well as the SUM of salaries. You are gathering data from the employees table. Use Grouping Sets to show the following groupings:
department_id, manager_id, job_id,
manager_id, job_id
Write the code step by step and explain it.