SWQL Syntax: List of SWQL (NOT SQL) Arithmetic Operators, Keywords and Logic Operators

I've been googling the past hour and looking for a list of operators (arithmetic and logic) and all the keywords used to construct SWQL filters and queries.

So far I've found six or so different resources that give about ten examples of the "=" operator and ten examples of the "LIKE" operator which does not seem to be a comprehensive guide.

Wildcards were mentioned but it doesn't say if you can use more than one in your query -->  somevariable LIKE '%foo%' matching 'myfoobar' and 'foobar' 

Is that it?   Is that all there is?   What about "NOT LIKE", which is what I'm really after in the immediate sense?  Is there an equivalent?   The resources I found also mention that it's a read only "subset" of SQL, (I am assuming they mean MSSQL) but there isn't any real definition of what that subset actually is.

Is there a resource available somewhere that I can find this information?