title: How to do the minus operation given 2 columns using mysql
body: <p>allpairs</p>
  <pre><code>user1 user2
  1     1
  2     1
  3     1
  1     2
  2     2
  3     2
  1     3
  2     3
  3     3
  </code></pre>
  <p>likesPairs</p>
  <pre><code>user1 user2
  1     2
  2     1
  3     1
  </code></pre>
  <p>I want to do allPairs - likedPairs to get the relation</p>
  <p>notliked</p>
  <pre><code>user1 user2
  1     1
  2     2
  3     2
  1     3
  2     3
  3     3
  </code></pre>
  <p>I tried something like this but it just errors</p>
  <pre><code>select user1, user2 
  from allpairs NOT IN likespairs
  </code></pre>