如何将我的前5名薪水和后5名薪水结合起来显示在Oracle中？

Question

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，但仅显示底部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;

Answer 1

使用UNION或UNION ALL：

SELECT SAL FROM
(
SELECT DISTINCT SAL FROM EMP WHERE SAL IS NOT NULL ORDER BY SAL DESC
)
WHERE ROWNUM < 6
UNION ALL
SELECT SAL FROM
(
SELECT DISTINCT SAL FROM EMP WHERE SAL IS NOT NULL ORDER BY SAL ASC
)
WHERE ROWNUM < 6;

您也可以将其写得更简洁：

SELECT SAL
FROM (SELECT DISTINCT SAL,
             DENSE_RANK() OVER (ORDER BY sal) as seqnum_asc,
             DENSE_RANK() OVER (ORDER BY sal) as seqnum_desc
      FROM EMP
      WHERE SAL IS NOT NULL
     ) s
WHERE seqnum_asc < 6 OR seqnum_desc < 6;