Using the minus sign (-wordxyz) together with a 'by user' produces this error. OK with no 'by user'.
I think I've seen this long time ago, so probably not related to recent updates etc. No index.
Not unique table/alias: 'm'
File: /customers/1/xyz/httpd.www/forum/Sources/Search.php
Line: 1352
Note: It appears that your database may require an upgrade. Your forum's files are currently at version SMF 2.0.17, while your database is at version 2.0.7. The above error might possibly go away if you execute the latest version of upgrade.php.
I tested that on this site and another SMF site and only got:
"Did you forget to put something to search for?"
I have this tracked internally as an issue already. Internal bug track id #71
1st enter what one searches for. Then add -whatever to be omitted from results.
Example: forum -search
ok, so it's already 'bugged' :O)
Thanks