By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
WITH yourTable AS (
SELECT 1 AS id, 'AB.1234.cd' AS string UNION ALL
SELECT 2, 'EF.5678.gh'
)
SELECT id, string, SUBSTRING_INDEX(SUBSTRING_INDEX(string, '.', -2), '.', 1) AS output
FROM yourTable;
| id | string | output |
|---|---|---|
| 1 | AB.1234.cd | 1234 |
| 2 | EF.5678.gh | 5678 |