Oracle 18c

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CREATE TABLE table1 (col1) AS
SELECT 'a' FROM DUAL UNION ALL
SELECT 'b' FROM DUAL UNION ALL
SELECT 'c' FROM DUAL;
3 rows affected

SELECT *
FROM   table1
       CROSS JOIN (SELECT LEVEL AS col2 FROM DUAL CONNECT BY LEVEL <= 3);


COL1
COL2


a
1

b
1

c
1

a
2

b
2

c
2

a
3

b
3

c
3


WITH data (col1, col2) AS (
  SELECT col1, 1 FROM table1
UNION ALL
  SELECT col1, col2 + 1 FROM data WHERE col2 < 3
)
SELECT * FROM data;


COL1
COL2


a
1

b
1

c
1

a
2

b
2

c
2

a
3

b
3

c
3