Oracle 18c

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CREATE TABLE percent_forest(country VARCHAR(10), pcnt_forest NUMBER(10,4))
INSERT INTO percent_forest
VALUES ('A', 0.05)
1 rows affected

INSERT INTO percent_forest
VALUES ('B', 0.06)
1 rows affected

INSERT INTO percent_forest
VALUES ('C', 0.07)
1 rows affected

INSERT INTO percent_forest
VALUES ('D', 0.51)
1 rows affected

INSERT INTO percent_forest
VALUES ('E', 0.49)
1 rows affected

INSERT INTO percent_forest
VALUES ('F', 0.96)
1 rows affected

INSERT INTO percent_forest
VALUES ('G', 0.97)
1 rows affected

INSERT INTO percent_forest
VALUES ('H', 0.98)
1 rows affected

SELECT country,  pcnt_forest
       ,WIDTH_BUCKET(pcnt_forest, 0, 1, 4) AS w
       ,NTILE(4) OVER(ORDER BY pcnt_forest) AS ntile  -- for comparison
FROM percent_forest
ORDER BY w


COUNTRY
PCNT_FOREST
W
NTILE


A
.05
1
1

B
.06
1
1

C
.07
1
2

E
.49
2
2

D
.51
3
3

F
.96
4
3

G
.97
4
4

H
.98
4
4