We have been working with WHERE to limit our output.

  SELECT table1.field1, table1.field2...
    table2.field1, table2.field2...
  FROM table1
  INNER|LEFT|RIGHT JOIN table2
    ON table1.shared_field1 = table2.shared_field1
  WHERE table1.field2 = some_value;

We have also seen the differences between INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL JOIN.

Download the class notes for day 5.