title: Select all rows from MySQL table with non-existent relation as empty cell
body: <p>If I had for example two tables called 'teachers' and 'lessons' and 'lessons' has a foreign key 'teacher_ID' referring to its counterpart in the 'teachers' table, then how would I select <strong>all</strong> rows from teacher with <strong>all</strong> of their corresponding lessons with an empty cell if no lesson is connected to them? I  only was able to make MySQL show me the teachers that <strong>have</strong> one or more lessons attached.</p>
  
  <p>Is this even possible without LEFT JOIN? I couldn't find anything on Google...</p>
  
  <p><strong>EDIT</strong>
  I was interested in the mechanics of the LEFT JOIN keyword. But since there doesn't seem to be an alternative I'd say <em>case closed</em>.</p>