Sounds less like SQL, and more like Docker and is an issue unrelated to n8n.
You have to understand that if something runs in Docker, it is like a second totally independent computer. So one can not see the files of the other unless you configure them accordingly.
Meaning you either have to export the workflows to a folder that is already mounted (that is what it is called in Docker when both share a folder) or you have to create a new mount.
One folder that is mounted by default on both systems is ~/n8n, as that is where n8n keeps its files. So you could export it to that folder.
A new mount can be done (in docker-compose) in the section “volumes”:
Generally, really always warn self-hosting n8n for production use without proper experience doing so. Especially without any experience with Docker. That is dangerous and always results in major downtime and/or data loss. The right option there is n8n cloud, as then our DevOps team is taking care of that.