title: MySQL Trigger to prevent INSERT under certain conditions
body: <p>I want to make a trigger that will prevent the insertion if the birthdate (one of the columns) is in the future. I have this:</p>
  
  <pre><code>CREATE TRIGGER foo
  BEFORE INSERT ON table
  FOR EACH ROW
  BEGIN
    IF NEW.birthdate &gt; CURRENT_DATE()
    THEN
      //How do I prevent the insert right here???
    END IF;
  END;
  </code></pre>
  
  <p>How can I cancel the insert inside the if statement?</p>