Compile the "join" clauses for an update.

        :param query: A QueryBuilder instance
        :type query: QueryBuilder

        :return: The compiled sql
        :rtype: str

def _compile_update_join_wheres(self, query):
        """
        Compile the "join" clauses for an update.

        :param query: A QueryBuilder instance
        :type query: QueryBuilder

        :return: The compiled sql
        :rtype: str
        """
        join_wheres = []

        for join in query.joins:
            for clause in join.clauses:
                join_wheres.append(self._compile_join_constraints(clause))

        return " ".join(join_wheres)