title: The best way to Find entries missing after inner-join?
body: <p>Lets suppose that we have the following 3 tables</p>
  <pre><code>Animal
  
  id name
  1 dog
  2 cat
  3 crow
  
  
  Actions
  
  id name
  1 run
  2 walk
  3 jump
  4 fly
  5 puppy_eyes
  6 swim
  
  Animal_Actions
  id Animal_id action_id
  1 1 1
  2 1 2
  3 1 3
  4 1 5
  5 2 1
  6 2 2
  7 2 3
  8 3 2
  9 3 4
  </code></pre>
  <p>I would like to find all the missing animal actions for certain animals</p>
  <p>For example if we input dog and cat( id 1 and 2) we should get the following <code>(1,4),(1,6),(2,4),(2,5), (2,6)</code></p>
  <p>and if we input crow (3) we get the following <code>(3,1),(3,3),(3,5), (3,6)</code> .</p>
  <p>Currently I'm doing an inner join between Animal and Animal_Actions table based on animal ID and importing this into a SET in my code and checking if every possible permutation is present in this set and collecting the missing ones. I'm not sure if the process I follow is the most efficient one, is there a better way to do this when the data is at a large scale ? Thanks in advance.</p>