1.Write the SQL code to count the number of ASSIGNMENT group by project number where assignment charging hour is greater than 40. Make sure your result is sort by project number desc.

2.Based on SQL code for problem 26, make sure you only show project number is greater than 20. In other word, write the SQL code to count the number of ASSIGNMENT group by project number where assignment charging hour is greater than 40 and end result only show project number is greater than 20.

3.Write the SQL code to generate following table (total, avg, max, sum of assign_charge of table Assignment) group by project number. Note that you have to get display format right with either col xxx format yyyy or function round.

4.Based on the SQL in problem 28, only select those projects total, avg, max, min, and sum of assign_charge with those related EMP_NUM whose hiring date is between 1/1/1990 and 12/31/1999. Your result should match following.

5.Write the SQL to generate a list of employee whose job_code is not in the list of job codes whose job charge hour in JOB table is greater than 100. Please note that Name format below (first name+middle initial+last name). You will have to learn how to use || string function. Your result should match following.