title: SQL: Relation between different rows of two tables
body: <p>I'm creating er-diagram for "Airport" database. And I got stick with tables "Flight" and "Airport" .
  In table "Flight" I have 2 columns: "Departure_place" and "Arrival_ place". Both of it should be connected to values in table "Airport".
  So, How can I make that in the proper way on er-diagram and on sql?</p>
  
  <p><a href="https://i.stack.imgur.com/Nx4Mv.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Nx4Mv.png" alt="enter image description here"></a></p>