instruction: Show the number of courses for each instructor in a bar chart, and I want to order in desc by the y axis.
response: SELECT EMP_FNAME, COUNT(EMP_FNAME) FROM CLASS AS T1 JOIN EMPLOYEE AS T2 ON T1.PROF_NUM = T2.EMP_NUM JOIN COURSE AS T3 ON T1.CRS_CODE = T3.CRS_CODE JOIN PROFESSOR AS T4 ON T2.EMP_NUM = T4.EMP_NUM GROUP BY EMP_FNAME ORDER BY COUNT(EMP_FNAME) DESC