Join Types

An inner join (sometimes called a simple join) returns only those rows that satisfy the join condition.

An outer join extends the result of a simple join. An outer join returns all rows that satisfy the join condition and also returns some or all of those rows from one table for which no rows from the other satisfy the join condition:

• A left outer join returns returns all rows from Table 1 and only rows meeting the join condition from Table 2. Rows in Table 1 that do not have a corresponding row in Table 2 have null values in the columns from Table 2.

• A right outer join returns returns all rows from Table 2 and only rows meeting the join condition from Table 1. Rows in Table 2 that do not have a corresponding row in Table 1 have null values in the columns from Table 1.

• A full outer join returns all rows from both or all tables. Rows in either table that do not have a corresponding row in the other table have null values in the columns from the other table.