is it possible to use the current database, empty it out, then import ?

unknown

Situation:  cannot create a brand new database, but can delete all the tables , ignoring the errors

Seeking for you suggestion:  how to move a jira instance (running, but some problem) to this 'kind of' empty database ? 

1. should I do a backup , then restore on jira instance which based on this empty database  to give it try ?
2. should I just do import database ? 

Goal: instance running on a different database with previous data.

Brant Schroeder

Quan,

  I would do a fresh install of the same version of JIRA.  This will create the database for you.  You can then point you JIRA instance at the new DB.  If you do this there will be lots of issues. if you do not migrate the DB content as well.  I think it would be better to address the issues you are having.  Can you explain what those issue are and what you are hoping to accomplish by moving DB?