Although I had no experience or knowledge on MyBB, I had to transfer another MyBB database to another forum I opened today, but I must have done something wrong while doing so. The error is: "MyBB SQL Error
MyBB has experienced an internal SQL error and cannot continue." I deleted all existing tables and imported my database. I would appreciate it if you could help with what the problem could be. Thank you.
The error you describe is too generic to hazard a guess. Don't know the versions of MyBB you're taking about, what plugins, if the host, location and/or protocol has changed - and a bunch of other things.
If you can 't access the ACP to turn on error logging in MyBB, you should check your web server error logs for additional info. See this thread for more discussion:
https://community.mybb.com/thread-143466.html
When you say "deleted all existing tables and imported my database" - assuming you mean the mybb tables from a recent install. Is the account info for the DB even the same - or did you use another privileged account?
Edit: Forgot to link to the mybb docs for moving hosts. Which is similar in some respects, excepting the new version of mybb. Which is another thing entirely.
https://docs.mybb.com/1.8/faq/moving-to-a-new-web-host/
Thank you so much! I'll look the links you sent and try to apply instructions but actually I'm totally lost, I can't even answer your questions.