So I've implemented the sunspot_rails gem into my application to utilize the powerful Solr search engine. I recently checked out Ryan's railscast on full-text searching and I noticed he was using additional parameters in his search queries such as "-" to denote something that should NOT be including in the full-text search.
I never heard about this until now, I was wondering if there was a user-friendly usage guide somewhere both me and my users can reference to take my search functionality to it's maximum capability.
I think ideally I would like to make an abridged version similar to Github's markdown cheat-sheet for my search forms that users can quickly reference.
Sunspot uses Solr's DisMax Query Parser, which has a very simple query syntax. For the most part, it is intended to flexibly parse user-created queries.
DisMax recognizes three special characters: +, -, and ". From the documentation:
[DisMax] is designed to be support raw input strings provided by users with no special escaping.
'+'and'-'characters are treated as "mandatory" and "prohibited" modifiers for the subsequent terms. Text wrapped in balanced quote characters'"'are treated as phrases, any query containing an odd number of quote characters is evaluated as if there were no quote characters at all.
There are a few other "behind the scenes" options to tune the relevancy of matched documents. For example, "minimum match" specifies the number or proportion of "optional" fields (i.e., not prefixed with - or +) which must be present. As well as options to boost term matches in specific fields, or term matches within close proximity to each other, and so on.
In Sunspot, these are all exposed in the options parameter to the fulltext method, or as methods within a block supplied to that method.
来源：https://stackoverflow.com/questions/12061573/rails-3-sunspot-fulltext-search-usage