交叉引用最近日期数据
cross reference nearest date data
我有三个tableElecUser
,ElecUsage
,ElecEmissionFactor
ElecUser:
UserID UserName
1 Main Building
2 Staff Quarter
ElecUsage:
UserID Time Amount
1 1/7/2010 23230
1 8/10/2011 34340
1 8/1/2011 34300
1 2/3/2012 43430
1 4/2/2013 43560
1 3/2/2014 44540
2 3/6/2014 44000
ElecEmissionFactor:
Time CO2Emission
1/1/2010 0.5
1/1/2011 0.55
1/1/2012 0.56
1/1/2013 0.57
预期结果:
UserName Time CO2
1 2010 11615
1 2011 37752 (34340*0.55 + 34300*0.55)
1 2012 24320.8
1 2013 24829.2
1 2014 25387.8
2 2014 25080
逻辑是 ElecUsage.Amount * ElecEmissionFactor。
如果是同一用户,同一年份,则将它们相加作为当年的记录。
我的查询是:
SELECT ElecUser.UserName, Year([ElecUsage].[Time]), SUM((ElecEmissionFactor.CO2Emission*ElecUsage.Amount)) As CO2
FROM ElecEmissionFactor, ElecUser INNER JOIN ElecUsage ON ElecUser.UserID = ElecUsage.UserID
WHERE (((Year([ElecUsage].[Time]))>=Year([ElecEmissionFactor].[Time])))
GROUP BY ElecUser.UserName, Year([ElecUsage].[Time])
HAVING Year([ElecUsage].[Time]) = Max(Year(ElecEmissionFactor.Time));
但是,这只显示有排放因子的年份。
挑战是将没有排放因子的年份参考最近有排放因子的年份。
子查询可能是解决方案之一,但我没有这样做。
我卡住了一段时间。希望看到你的回复。
谢谢
试试这样的..
-- 未测试
select T1.id, year(T1.time) as Time, sum(T1.amount*T2.co2emission) as CO2
from ElecUsage T1
left outer join ElecEmissionFactor T2 on (year(T1.time) = year(T2.time))
Group by year(T1.time), T1.id
这样使用子查询得到对应的因子
select T1.id,
year(T1.time) as Time,
sum(T1.amount*
(
select top 1 CO2Emission from ElecEmissionFactor T2
where year(T2.time) <= year(T1.time) order by T2.time desc
)
) as CO2
from ElecUsage T1
Group by year(T1.time), T1.id
我有三个tableElecUser
,ElecUsage
,ElecEmissionFactor
ElecUser:
UserID UserName
1 Main Building
2 Staff Quarter
ElecUsage:
UserID Time Amount
1 1/7/2010 23230
1 8/10/2011 34340
1 8/1/2011 34300
1 2/3/2012 43430
1 4/2/2013 43560
1 3/2/2014 44540
2 3/6/2014 44000
ElecEmissionFactor:
Time CO2Emission
1/1/2010 0.5
1/1/2011 0.55
1/1/2012 0.56
1/1/2013 0.57
预期结果:
UserName Time CO2
1 2010 11615
1 2011 37752 (34340*0.55 + 34300*0.55)
1 2012 24320.8
1 2013 24829.2
1 2014 25387.8
2 2014 25080
逻辑是 ElecUsage.Amount * ElecEmissionFactor。
如果是同一用户,同一年份,则将它们相加作为当年的记录。
我的查询是:
SELECT ElecUser.UserName, Year([ElecUsage].[Time]), SUM((ElecEmissionFactor.CO2Emission*ElecUsage.Amount)) As CO2
FROM ElecEmissionFactor, ElecUser INNER JOIN ElecUsage ON ElecUser.UserID = ElecUsage.UserID
WHERE (((Year([ElecUsage].[Time]))>=Year([ElecEmissionFactor].[Time])))
GROUP BY ElecUser.UserName, Year([ElecUsage].[Time])
HAVING Year([ElecUsage].[Time]) = Max(Year(ElecEmissionFactor.Time));
但是,这只显示有排放因子的年份。
挑战是将没有排放因子的年份参考最近有排放因子的年份。
子查询可能是解决方案之一,但我没有这样做。
我卡住了一段时间。希望看到你的回复。
谢谢
试试这样的..
-- 未测试
select T1.id, year(T1.time) as Time, sum(T1.amount*T2.co2emission) as CO2
from ElecUsage T1
left outer join ElecEmissionFactor T2 on (year(T1.time) = year(T2.time))
Group by year(T1.time), T1.id
这样使用子查询得到对应的因子
select T1.id,
year(T1.time) as Time,
sum(T1.amount*
(
select top 1 CO2Emission from ElecEmissionFactor T2
where year(T2.time) <= year(T1.time) order by T2.time desc
)
) as CO2
from ElecUsage T1
Group by year(T1.time), T1.id