SELECT DISTINCT
SELECT DISTINCT DEPT_NO
FROM EMP
WHERE (SELECT AVG(EMP1.EMP_SAL)
FROM EMP EMP1
WHERE EMP1.DEPT_NO = EMP.DEPT_NO) > 12000.00;
Введение в модель данных SQL
SELECT DISTINCT DEPT_NO
FROM EMP
WHERE (SELECT AVG(EMP1.EMP_SAL)
FROM EMP EMP1
WHERE EMP1.DEPT_NO = EMP.DEPT_NO) > 12000.00;