Oracle 18c

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CREATE TABLE table1 (col1) AS
SELECT LEVEL FROM DUAL CONNECT BY LEVEL <= 5;
5 rows affected

SELECT col1 FROM table1;

COL1

1

2

3

4

5

SELECT col1 FROM table1 WHERE ROWNUM < 2 ORDER BY col1 DESC;

COL1

1

SELECT MAX(col1) FROM table1;

MAX(COL1)

5

SELECT col1 FROM (
  SELECT col1 FROM table1 ORDER BY col1 DESC
)
WHERE ROWNUM < 2;

COL1

5

SELECT col1 FROM table1 ORDER BY col1 DESC FETCH FIRST ROW ONLY;

COL1

5