On the sample dataset db_employees:
- Compute the number of employees hired in each year
- Find the manager (that is, employee that do not report to any other person), who have been hired the longest time.
- Find the orders with the longest time between the submission and the approval.
- Find the order that has the most items
- Compute how the current number of units in stock is distributed among all categories
- Find the categories with the largest number of items in stock.