We have started a new course. Always keep in mind that the heart of SQL is the SELECT statement.

SELECT table1.field1,
  table1.field2,
  table2.field1,
  table2.field2 ...
FROM table1
INNER/LEFT/RIGHT JOIN table2
  ON table1.common_field1 = table2.common_field1
    AND table1.common_field2 = table2.common_field2

Download the notes for day 1.