Введение в модель данных SQL


Пример 15.12.1


SELECT DEPT_NO, AVG (CURRENT_DATE - EMP_BDATE)

FROM EMP

WHERE DEPT_NO IS NOT NULL

GROUP BY DEPT_NO

HAVING NOT EXISTS (SELECT EMP1.DEPT_NO

FROM EMP EMP1

WHERE EMP1.DEPT_NO IS NOT NULL

GROUP BY EMP1.DEPT_NO

HAVING AVG (CURRENT_DATE - EMP1.EMP_BDATE) <

AVG (CURRENT_DATE - EMP.EMP_BDATE));




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