I have imported a user from GoogleApps and i know the user correlates to an active Okta user(without the GoogleApps) but as they have nothing in common(name,email), i can't find a way to assign the imported user to the active one.
When the import is run the source users are assigned to Okta users. In your case you can match the Google user to an Okta user. In the picture below my Active Directory user is assigned to an Existing Okta user that I specify. Click on the Okta User Assigment for more options.