查询性能与优化
查询性能与优化
提问于 2015-04-09 12:56:32
希望优化Oracle查询。选择一个月的数据，需要24-26秒才能显示数据.它是否有可能优化，完善它，它需要较少的时间在5-10秒左右。您的反馈非常感谢。
select eutrancellfdd,
startdate,
max(connected_users)
from
(select eutrancellfdd,
startdate,
starthour,
Round((case when pmrrcconnlevsamp_sum = 0 then 0
else (pmrrcconnlevsum/pmrrcconnlevsamp_sum) end),0) as connected_users
from tblericsson)
group by eutrancellfdd, startdate
Having startdate between to_date('03/01/2015','MM/DD/YYYY')
AND to_date('04/01/2015','MM/DD/YYYY')
and eutrancellfdd='L0253401'
order by startdate asc; 回答 1
Stack Overflow用户
回答已采纳
发布于 2015-04-09 13:20:06
尝试使用此查询。此外，请检查列中是否有索引，如eutrancellfdd和startdate。
select eutrancellfdd,
startdate,
max(Round((case when pmrrcconnlevsamp_sum = 0 then 0
else (pmrrcconnlevsum/pmrrcconnlevsamp_sum) end),0))
from
where startdate between to_date('03/01/2015','MM/DD/YYYY')
AND to_date('04/01/2015','MM/DD/YYYY')
and eutrancellfdd='L0253401'
group by eutrancellfdd, startdate
order by startdate asc; 页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/29539133
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