SELECT D.dname, L.dlocation
FROM DEPARTMENT D, dept_locations L
Выход:
dname dlocation
Research Houston
Research Stafford
Research Bellaire
Research Houston
Research Sugarland
Administration Houston
Administration Stafford
Administration Bellaire
Administration Houston
Administration Sugarland
Headquarters Houston
Headquarters Stafford
Headquarters Bellaire
Headquarters Houston
Headquarters Sugarland
Желаемый результат:
dname dlocation
Headquarters Houston
Administration Stafford
Research Bellaire
Research Houston
Research Sugarland
Вам нужно внутреннее соединение
SELECT D.dname, L.dlocation
FROM DEPARTMENT D inner join dept_locations L
on d.departmentid=l.departmentid
JOIN
. Легче писать (без ошибок), легче читать и обслуживать, и при необходимости легче конвертировать во внешнее соединение!