INNER join vs OUTER joins

• In SQL: 1999, the join of two ables returning only matched rows is called inner join.
  
  
• A join between two tables that returns the results of the inner join as well as the unmatched rows from the left(or right) tables is called a left(or right) outer join.
  
  
• A join between two tables that returns the results of an inner join as well as the results of a left and right join is a full outer join.