This section describes the migration syntax of Oracle OUTER JOIN. The migration syntax determines how the keywords/features are migrated.

An OUTER JOIN returns all rows that meet the join condition. If rows of a table cannot join any rows in the other table, the statement returns these rows. In Oracle:

Left outer join of tables A and B returns all rows from A and rows that satisfy the join condition by applying the outer join operator (+) to all columns of B in the WHERE conditions.
Right outer join of tables A and B returns all rows from B and rows that satisfy the join condition by applying the outer join operator (+) to all columns of A in the WHERE condition.

GaussDB(DWS) does not support the + operator. The function of this operator is enabled using LEFT OUTER JOIN and RIGHT OUTER JOIN keywords.

Figure 1 Input: OUTER JOIN

Figure 2 Output: OUTER JOIN