Sql 优化子select语句以减少获取时间

我有一个问题

select * from 
(select a.*, /*+ FIRST_ROWS(10) */ rownum rnum 
 from (SELECT AL.AL_UID, AL.TP_ID, AL.EVENTDATE, TP.NAME, AL.EVENT, AL.FILE_NAME,
              AL.NOTES, AL.XU_NAME, AL.STATUS, AL.LOG_SOURCE, rownum
       FROM AUDITLOG AL,
            TRADINGPARTNER TP 
       WHERE  ( AL.LOG_SOURCE = 'File Deployment' )  AND TP.ID = AL.TP_ID 
       ORDER BY AL.EVENTDATE desc, AL.AL_UID desc
      ) a
 where rownum < 101
) 
where rnum > 0;

---

获取结果大约需要一分钟的时间。请让我知道如何优化它，以减少获取时间。我可以在这里使用联接吗？

关于日志源、EVENTDATE desc、AL\u UID desc的索引值得一看-可能不需要desc子句，如果可能，尽量不要使用它们

---

我会将第一行提示放在与谓词和order相同的查询块中。

窗口函数通常比order by快。您可以尝试以下方法：

select *
from (SELECT AL.AL_UID, AL.TP_ID, AL.EVENTDATE, TP.NAME, AL.EVENT, AL.FILE_NAME,
             AL.NOTES, AL.XU_NAME, AL.STATUS, AL.LOG_SOURCE,
             ROW_NUMBER() over (order by AL.EVENTDATE desc, AL.AL_UID desc) as seqnum
      FROM AUDITLOG AL join
           TRADINGPARTNER TP 
           on TP.ID = AL.TP_ID
      WHERE AL.LOG_SOURCE = 'File Deployment'
     ) t
where seqnum between 1 and 100;

有了它，您实际上可以这样写：

select al.*, TP.name
from (SELECT AL.AL_UID, AL.TP_ID, AL.EVENTDATE, AL.EVENT, AL.FILE_NAME,
             AL.NOTES, AL.XU_NAME, AL.STATUS, AL.LOG_SOURCE,
             ROW_NUMBER() over (order by AL.EVENTDATE desc, AL.AL_UID desc) as seqnum
      FROM AUDITLOG AL
      WHERE AL.LOG_SOURCE = 'File Deployment'
     ) al join
     TradingPartner tp
     on TP.ID = AL.TP_ID 
where seqnum between 1 and 100;

---

很明显，AuditLogEventdate上的索引将大大提高性能。

您真正想要的是什么输出？是否要所有列？如果可能的话，请告诉我们您想要的输出。您不能只有一个子查询而不是两个子查询吗？其中rownum<101和rnum>0应该起到关键作用否？事实上，我认为不需要任何子查询。此外，log_source上的索引可能会有所帮助。@DanBracuk:where子句在order by之前求值，因此必须有一级子查询以确保在按行号筛选之前应用order by-请参阅。感谢您的解释。在审计日志表的EVENT_DATE列上添加索引就成功了。谢谢