A LEFT OUTER JOIN includes all rows from the left table and all matching rows from the right table. Any left-table rows without matching right-table rows will have nulls returned for the missing selected values. The order of tables in a LEFT OUTER JOIN are critical and can not be rearranged.

                                               LEFT OUTER JOIN syntax:

                                   SELECT t1.column1 AS ‘title1′,
                                                t2.column2 AS ‘title2′, …
                                      FROM left_table                         [AS] ‘t1′
                                       LEFT [OUTER] JOIN right_table [AS] ‘t2′
                                          ON left_t1.column1 oper right_t2.column2[, ...]
                                  [GROUP BY t1.column1]
                                  [HAVING      t1.column1]
                                  [ORDER BY t1.column1 [ASC|DESC]]

If the tables have common column names, those column names must be qualified with the table name or alias as follows: [left_table.]column oper [right_table.]column.

> While LEFT OUTER JOINs can be done occasionally without the key word OUTER, the word OUTER should normally be included in the OUTER JOIN statement for clarity of understanding.

> Oracle 9i and later supports the LEFT OUTER JOIN, but it also has the non-standard (+) outer join operator.

> SQL Server supports LEFT OUTER JOIN, but it also has the non-standard outer join * in the WHERE syntax.