title: Select Only Rows With Different Value of Both Rows
body: <p>I have tbl_user, tbl_friendship</p>
  
  <pre><code>- tbl_user
  uid username
  1     Joun
  2     Bun
  3     Meu
  4     Nux
  5     Zii
  
  - tbl_friendship
  friend_1 friend_2 status
  1        2        1
  1        3        1
  1        4        0
  5        1        1
  2        3        1
  </code></pre>
  
  <p>friend_1 and friend_2 is FK to tbl_user.uid</p>
  
  <p>status 1 mean friend_1 and friend_2 are friends.
  status 0 mean friend_1 sends friend_2 a request but friend_2 is not accept it.</p>
  
  <p>How to show all user who are friends with user Joun (uid 1). The expected result is :</p>
  
  <pre><code>2
  3
  5
  </code></pre>
  
  <p>I tried</p>
  
  <pre><code>SELECT friend_1, friend_2 FROM tbl_friendship
  WHERE status = 1 AND friend_1 = 1 OR friend_2 = 1
  </code></pre>
  
  <p>result :</p>
  
  <pre><code>friend_1 friend_2
  1        2
  1        3
  5        1
  </code></pre>