Referrals Duplicates due to url case insensitive in table

hello everybody,

I’m migrating my old ojs 2.3 database that is in postgres to MySQL. At the process I’ve detected some errors because of case-insensitive in url column from referrals table in mySQL db. I’ve checked all registries that appear duplicated and the query returned more than 100 entries that will fail in migration process.

select article_id, status, upper(url), count()
from referrals
group by article_id,status, upper(url)
having count(
) > 1

checking some url column content, this seems that the url link is not valid.

If I want to migrate after to OJS 3.1. could I delete all referral content and what are the implications?

thank you so much