By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
| CONCAT(SUBSTR(email, 1, 3), '0', SUBSTR(email, 4)) |
|---|
| aa-0001@test.me |
| REGEXP_REPLACE(email, '^(.{3})(.{11})$', CONCAT('$1', '0', '$2')) |
|---|
| aa-0001@test.me |
| bb-0002@test.me |