title: Mysql set default value if entry does not exist
body: <p>When I execute the following query :-</p>
  
  <pre><code>SELECT users.id, users.username, users.last_login,
  profile_pictures.pic_resized, profile_pictures.pic_blurred, 
  user_profile.date_of_birth,  user_profile.u_country,
  matches.total_score AS score,
  favorites.id AS is_favorite,
  relationships.id AS is_match,
  profile_visitors.id AS is_profile_viewer,
  block_chat.id AS is_blocked
  FROM users
  INNER JOIN user_profile ON users.id = user_profile.user_id
  LEFT JOIN profile_pictures ON users.id = profile_pictures.user_id
  LEFT JOIN match_collections ON users.id = match_collections.user_id AND match_collections.status='valid'
  LEFT JOIN matches ON matches.collection_id = match_collections.id AND match_id = 44700
  LEFT JOIN favorites ON favorites.subject_id = 11354 AND favorites.object_id = 44700
  LEFT JOIN relationships ON relationships.user_id = 11354 AND relationships.friend_id = 44700
  LEFT JOIN profile_visitors ON profile_visitors.viewed_id = 11354 AND profile_visitors.viewer_id = 44700
  LEFT JOIN block_chat ON block_chat.subject_id = 11354 AND block_chat.object_id = 44700
  WHERE users.id = 11354
  </code></pre>
  
  <p>The result appear:<img src="https://i.stack.imgur.com/SXOGg.png" alt="enter image description here">
  where is_favorite and is_match is null which refer that there are no entry for the user 44700 in those tables.</p>
  
  <p>The question is: How to set a default value like <code>-1</code> instead of <code>NULL</code>?.</p>