SQL functions RANK(), PERCENT_RANK(), CUME_DIST() and NTILE()

test_rank.sql

CREATE TABLE test_rank (
    i   integer,
    s   varchar(1)
);

INSERT INTO test_rank (i, s) VALUES (1, 'A');
INSERT INTO test_rank (i, s) VALUES (2, 'B');
INSERT INTO test_rank (i, s) VALUES (2, 'b');
INSERT INTO test_rank (i, s) VALUES (3, 'D');
INSERT INTO test_rank (i, s) VALUES (4, 'E');

SELECT
    ROW_NUMBER() OVER (ORDER BY i),
    RANK() OVER (ORDER BY i),
    DENSE_RANK() OVER (ORDER BY i),
    PERCENT_RANK() OVER (ORDER BY i),
    CUME_DIST() OVER (ORDER BY i),
    NTILE(4) OVER (ORDER BY i),
    s
FROM test_rank ORDER BY i, s;


 row_number | rank | dense_rank | percent_rank | cume_dist | ntile | s 
------------+------+------------+--------------+-----------+-------+---
          1 |    1 |          1 |            0 |       0.2 |     1 | A
          2 |    2 |          2 |         0.25 |       0.6 |     1 | B
          3 |    2 |          2 |         0.25 |       0.6 |     2 | b
          4 |    4 |          3 |         0.75 |       0.8 |     3 | D
          5 |    5 |          4 |            1 |         1 |     4 | E
(5 rows)