RIGHT OUTER JOIN

RIGHT OUTER JOIN RIGHT OUTER JOIN expression

A RIGHT OUTER JOIN is one of the JOIN operationss that allow you to specify a JOIN clause. It preserves the unmatched rows from the second (right) table, joining them with a NULL in the shape of the first (left) table. A LEFT OUTER JOIN B is equivalent to B RIGHT OUTER JOIN A, with the columns in a different order.

SyntaxTableExpression RIGHT [ OUTER ] JOIN TableExpression { ON booleanExpression }

The scope of expressions in the ON clause includes the current tables and any tables in query blocks outer to the current SELECT. The ON clause can reference tables not being joined and does not have to reference either of the tables being joined (though typically it does).

Example 1-- get all countries and corresponding cities, including -- countries without any cities SELECT COUNTRIES.COUNTRY, CITIES.CITY_NAME FROM CITIES RIGHT OUTER JOIN COUNTRIES ON CITIES.COUNTRY_ISO_CODE = COUNTRIES.COUNTRY_ISO_CODE; -- get all countries in Africa and corresponding cities, including -- countries without any cities SELECT COUNTRIES.COUNTRY, CITIES.CITY_NAME FROM CITIES RIGHT OUTER JOIN COUNTRIES ON CITIES.COUNTRY_ISO_CODE = COUNTRIES.COUNTRY_ISO_CODE WHERE Countries.region = 'Africa'; -- use the synonymous syntax, RIGHT JOIN, to achieve exactly -- the same results as in the example above SELECT COUNTRIES.COUNTRY, CITIES.CITY_NAME FROM CITIES RIGHT JOIN COUNTRIES ON CITIES.COUNTRY_ISO_CODE = COUNTRIES.COUNTRY_ISO_CODE WHERE Countries.region = 'Africa'; Example 2-- a TableExpression can be a joinOperation. Therefore -- you can have multiple join operations in a FROM clause -- List every employee number and last name -- with the employee number and last name of their manager SELECT E.EMPNO, E.LASTNAME, M.EMPNO, M.LASTNAME FROM EMPLOYEE E RIGHT OUTER JOIN DEPARTMENT RIGHT OUTER JOIN EMPLOYEE M ON MGRNO = M.EMPNO ON E.WORKDEPT = DEPTNO;