PostgreSQL — Window functions

1 PostgreSQL ROW_NUMBER ranking Hard 2 PostgreSQL ROW_NUMBER partition #1 Hard 3 PostgreSQL ROW_NUMBER partition #2 Medium 4 PostgreSQL ROW_NUMBER partition #3 Medium 5 PostgreSQL ROW_NUMBER partition #4 Hard 6 PostgreSQL ROW_NUMBER partition #5 Medium 7 PostgreSQL ROW_NUMBER partition #6 Medium 8 PostgreSQL ROW_NUMBER partition #7 Hard 9 PostgreSQL ROW_NUMBER partition #8 Medium 10 PostgreSQL ROW_NUMBER partition #9 Medium 11 PostgreSQL ROW_NUMBER partition #10 Hard 12 PostgreSQL ROW_NUMBER partition #11 Medium 13 PostgreSQL ROW_NUMBER partition #12 Medium 14 PostgreSQL ROW_NUMBER partition #13 Hard 15 PostgreSQL ROW_NUMBER partition #14 Medium 16 PostgreSQL ROW_NUMBER partition #15 Medium 17 PostgreSQL ROW_NUMBER partition #16 Hard 18 PostgreSQL ROW_NUMBER partition #17 Medium 19 PostgreSQL ROW_NUMBER partition #18 Medium 20 PostgreSQL ROW_NUMBER partition #19 Hard 21 PostgreSQL ROW_NUMBER partition #20 Medium 22 PostgreSQL ROW_NUMBER partition #21 Medium 23 PostgreSQL ROW_NUMBER partition #22 Hard 24 PostgreSQL ROW_NUMBER partition #23 Medium 25 PostgreSQL ROW_NUMBER partition #24 Medium 26 PostgreSQL ROW_NUMBER partition #25 Hard 27 PostgreSQL ROW_NUMBER partition #26 Medium 28 PostgreSQL ROW_NUMBER partition #27 Medium 29 PostgreSQL ROW_NUMBER partition #28 Hard 30 PostgreSQL ROW_NUMBER partition #29 Medium 31 PostgreSQL ROW_NUMBER partition #30 Medium