new

# File activerecord/lib/arel/nodes/select_core.rb, line 9
      def initialize(relation = nil)
        super()
        @source = JoinSource.new(relation)

        # https://ronsavage.github.io/SQL/sql-92.bnf.html#set%20quantifier
        @set_quantifier  = nil
        @optimizer_hints = nil
        @projections     = []
        @wheres          = []
        @groups          = []
        @havings         = []
        @windows         = []
        @comment         = nil
      end