Tabela Departamento (DEPT)

DEPTNO	DEPTNAME
A01	ACCOUNTING
A02	PAYROLL
A03	OPERATIONS
A04	PERSONNEL
A05	MAINTENANCE

Tabela Empregados (EMP)

EMPNO	WORKDEPT
5001	A01
5002	A04
5003	A03
5004	A03
5005	A04
5006	A04
5007	A03
5008	A06

Left outer join

SELECT	A.DEPTNO, A.DEPTNAME, B.EMPNO
	FROM PW0001.DEPT A
	LEFT JOIN PW0001.EMP B
	ON A.DEPTNO = B.WORKDEPT

Tabela Resultado

DEPTNO	DEPTNAME	EMPNO
A01	ACCOUNTING	5001
A02	PAYROLL	<null>
A03	OPERATIONS	5003
A03	OPERATIONS	5004
A03	OPERATIONS	5007
A04	PERSONNEL	5002
A04	PERSONNEL	5005
A04	PERSONNEL	5006
A05	MAINTENANCE	<null>

Cada linha unmatched da tabela DEPT é combinada com uma linha nula da tabela EMP.