Använd UNION
eller 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;
Du kan också skriva detta mer kortfattat som:
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;