I have installed the free version of DB Replacer - J!4 website. I`m trying to find and replace joomla-generated URLs that look like "index.php?option=com_content&view=article&id=1:indicatii-dupa-extractie-masea&catid=78" but no such strings are found - I know for sure I`m looking in the right Data Base and table. Would the premium version be more suitable for doing the job?
Are you sure that url is in the database like that?
Often URLs are a bit different in the database to how they are output in the frontend.
You can test this by searching for just part of it, or some HTML just before it. And see what the full URL looks like in the preview DB Replacer gives.