SQL — Aggregates & GROUP BY

1 Average salary by department Medium 2 Departments with total salary > 100000 Hard 3 Avg by category #1 Hard 4 Avg by category #2 Medium 5 Avg by category #3 Medium 6 Avg by category #4 Hard 7 Avg by category #5 Medium 8 Avg by category #6 Medium 9 Avg by category #7 Hard 10 Avg by category #8 Medium 11 Avg by category #9 Medium 12 Avg by category #10 Hard 13 Avg by category #11 Medium 14 Avg by category #12 Medium 15 Avg by category #13 Hard 16 Avg by category #14 Medium 17 Avg by category #15 Medium 18 Avg by category #16 Hard 19 Avg by category #17 Medium 20 Avg by category #18 Medium 21 Avg by category #19 Hard 22 Avg by category #20 Medium 23 Avg by category #21 Medium 24 Avg by category #22 Hard 25 Avg by category #23 Medium 26 Avg by category #24 Medium 27 Avg by category #25 Hard 28 Avg by category #26 Medium 29 Avg by category #27 Medium 30 Avg by category #28 Hard 31 Avg by category #29 Medium 32 Avg by category #30 Medium