title: MySQL getting coupons that have NOT been used
body: <p>I have 3 MySQL tables which hold information about a user, coupon information and if a user has used a coupon. Something like this: <br/>
  User Table <br/></p>
  
  <pre><code>+----------+-------------+
  | User_ID  | Name        |
  +----------+-------------+
  |    1     | Sarah J     |
  |    2     | John Smith  |
  |    3     | Osman Lee   |
  +----------+-------------+
  </code></pre>
  
  <p>Coupon Table <br/></p>
  
  <pre><code>+----------+-------------+
  | Coupon_ID| Title       |
  +----------+-------------+
  |    1     | Free Stuff  |
  |    2     | 50% Off     |
  |    3     | $5 off $25  |
  +----------+-------------+
  </code></pre>
  
  <p>And Redeemed Table<br/></p>
  
  <pre><code>+----------+---------+----------+
  | Coupon_ID| User_ID | Redeemed |
  +----------+---------+----------+
  |    1     |    1    |   yes    |
  |    2     |    2    |   yes    |
  |    1     |    2    |   yes    |
  +----------+---------+----------+
  </code></pre>
  
  <p>Basically I want this output for every user: <br/>
  Sarah J:    Coupons 2 &amp; 3 <br/>
  John Smith: Coupon 3 <br/>
  Osman Lee:  Coupon 1, 2 &amp; 3 <br/></p>
  
  <p>I tried using joins but no luck so far. Any suggestions? [For Sarah]</p>
  
  <pre><code>SELECT Coupons.coupon_id, Coupons.title
  FROM Coupons
  LEFT JOIN Redeemed ON Redeemed.coupon_id != Coupons.coupon_id
  WHERE Users.user_id = '1'
  </code></pre>