As mentioned in the release notes for 7.7.1
SugarQuery::joinRaw() has been deprecated.
The method is still in the 7.8 Documentation:
But the blog Use of prepared statements in Sugar 7.9 « Sugar Developer Blog – SugarCRM in "Things to watch out for in 7.9" states that SugarQuery::joinRaw has been removed.
Using as an example from Shane Dowling's blog:
How would you recommend going about replacing the JoinRaw used in
public function buildJoinSugarQuery