因此，我知道如何自行显示前5名和后5名。问题是如何将两者同时显示。这就是我所拥有的，但只显示底部的5。
SELECT SAL FROM
(
SELECT DISTINCT SAL FROM EMP WHERE SAL IS NOT NULL ORDER BY SAL DESC
)
WHERE ROWNUM <6 AND
SELECT SAL FROM
(
SELECT DISTINCT SAL FROM EMP WHERE SAL IS NOT NULL ORDER BY SAL ASC
)
WHERE ROWNUM <6;