few other solutions:
long thread with some interesting solutions:
https://www.ads-software.com/support/topic/disabling-multisite-db-error?replies=14
https://www.toprankblog.com/2009/07/repair-wordpress/
I would perhaps just update your wordpress installation manually by putting the latest files and not the wp-config.
Once done, just make sure your wpconfig file has the right settings to it.
