5)  state BETWEEN(order_date ,23/05/1995 , 28/06/1995)

                  6)  State NOT BETWEEN(order_date ,23/05/1995 , 28/06/1995)

          7)         State of filter switched off.

   If you look at all our states, you could never see equality of left and right side. It is always included in the nature of
object’s filtration. Let’s show it predefined state. For exempla:
            SELECT *;
                  FROM order;
                  WHERE order_date = 04/05/1995

                It seems a little complicated for operator equality. Unfortunately, a life could not be so easy.