1. Write a query to find the number of employees Joined in each year?

2. Write a query to display the number of people with the same job.

3. Display the highest, lowest, sum, and average salary of all employees. Label the columns
Maximum, Minimum, Sum, and Average, respectively. Round your results to the nearest whole
number. 

4. display the minimum, maximum, sum, and average salary for
each job type.

5. Display the manager number and the salary of the lowest paid employee for that manager.
Exclude anyone whose manager is not known. Exclude any groups where the minimum
salary is $6,000 or less. Sort the output in descending order of salary. 

6. Write a query that displays the difference between the highest and lowest salaries. Label the
column DIFFERENCE. 

7. Determine the number of managers without listing them. Label the column Number of
Managers. Hint: Use the MANAGER_ID column to determine the number of managers.