...
queries = []
joins = []
left_outer_joins = []
if query.present?
  left_outer_joins << :company
  left_outer_joins << {sessions: [:session_questions]}
  queries << "(cases.id::text ILIKE :query OR companies.name ILIKE :query OR session_questions.response ILIKE :query)"
  query_params[:query] = "%#{query}%"
end
if case_creator_id.present?
  queries << "(cases.case_creator_id = :case_creator_id)"
end
self.joins(joins)
    .left_outer_joins(left_outer_joins)
    .where(queries.join(" AND "), query_params)
    .distinct

get CASE_URL, params: { case_creator_id: creator.id, query: "Some Co. "}, headers: ...

"cases.id::text ILIKE :query OR companies.name ILIKE :query OR session_questions.response ILIKE :query AND cases.case_creator_id = :case_creator_id"