title: SQLite query select all records that does not exist in another table
body: <p>I am having some problem when trying to perform a SQLite query to get the records which does not exist from another table. Basically I have two database tables:</p>
  
  <p><img src="https://i.stack.imgur.com/ybTmD.png" alt="Database table"></p>
  
  <p>My exercise table stored all the exercises available whereas the bookedExercise table store the exercises booked by each users. What I am trying to do is, for example if the exercise does exist in the bookedExercise, it should be filtered out. </p>
  
  <p>Here is the SQLite query which I used:</p>
  
  <pre><code>SELECT exercise.exerciseID, exercise.exerciseType, exercise.amout FROM exercise LEFT JOIN bookedExercise WHERE exercise.exerciseID = bookedExercise.exerciseID AND bookedExercise.exerciseID IS NULL
  </code></pre>
  
  <p>However, it returned me empty records. Any ideas? </p>
  
  <p>Thanks in advance.</p>