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我有下面的查询。 SOFTWARE_DEVELOPMENT_CYCLE有多行,但我对最新版本感兴趣。Oracle - 用max()重构子查询
我想重写查询,以便我不使用子查询。我曾尝试过使用DENSE_RANK LAST ORDERY BY,但无济于事。
有人建议吗?谢谢。
SELECT SOF.VENDOR,
SOF.NAME,
LAN.LANGUAGE,
SOF.VERSION,
SDC.STATUS,
SDC.SOF_DC_ID
FROM SOFTWARE SOF
JOIN SOFTWARE_LANGUAGES SL
ON (SL.SOF_SOF_ID = SOF.SOF_ID)
JOIN LANGUAGES LAN
ON (SL.LAN_LAN_ID = LAN.LAN_ID)
JOIN SOFTWARE_DEVELOPMENT_CYCLE SDC
ON (SDC.SOF_LAN_SOF_LAN_ID = SL.SOF_LAN_ID)
WHERE SDC.SOF_DC_ID IN (SELECT MAX(SDC2.SOF_DC_ID)
FROM SOFTWARE_DEVELOPMENT_CYCLE SDC2
WHERE SDC2.SOF_LAN_SOF_LAN_ID = SL.SOF_LAN_ID)
ORDER BY SOF.VENDOR,
SOF.NAME,
LAN.LANGUAGE,
SOF.VERSION;
谢谢。你能否解释你的过程,以决定如何做到这一点? – retrodev 2012-02-23 16:48:22