If you have only one value in URL field, then you can start with this:
TABLE WITHOUT ID rows.file.link AS File, Link
WHERE URL
GROUP BY URL AS Link
WHERE length(rows.file.link) > 1
EDIT: or, at the end, using only WHERE length(rows) > 1
If you have only one value in URL field, then you can start with this:
TABLE WITHOUT ID rows.file.link AS File, Link
WHERE URL
GROUP BY URL AS Link
WHERE length(rows.file.link) > 1
EDIT: or, at the end, using only WHERE length(rows) > 1