search syntax in forum

what is the search syntax in the forum?
I searched for the term duplicate row and did not find a post.
Then i searched for duplicate row* and found a post with the title "duplicate rows". This means that * means wildcard.
I wonder if there is a document which explains what the search syntax is.

The forum search uses a MySQL fulltext index. Probably it's the best to rely just on Google here which has indexed nearly all posts.