我有一个查询,我认为应该很难做到,但是,现在我花了很多时间,仍然无法按照我想要的方式获取它,所以我希望这里有人能帮助我。SQL Server查询连接多个表
基本上,我需要创建一个报告,为每个区域提供每个月的价值。但是,并非所有地区每个月都会提供数据;在这种情况下,该视图应该在该月份和区域返回NULL。因此,认为需要看是这样的:
Month Area Value
2012-08-01 Area1 2
2012-08-01 Area2 3
2012-09-01 Area1 3
2012-09-01 Area2 NULL
我的数据表看起来像这样
Date Area Value
2012-08-01 Area1 2
2012-08-01 Area2 3
2012-09-01 Area1 3 -- Notice that Area2 is not present for September here
我有一个表的所有可用区域 此外,我创建了一个表 - 该函数返回从给定日期到现在的所有日期。
例如本声明
SELECT * FROM Periods_Months('2012-01-01')
将返回8条记录,如:
DateValue Year Month YearMonth
2012-01-01 00:00:00.000 2012 1 20121
2012-02-01 00:00:00.000 2012 2 20122
2012-03-01 00:00:00.000 2012 3 2
2012-04-01 00:00:00.000 2012 4 20124
2012-05-01 00:00:00.000 2012 5 20125
2012-06-01 00:00:00.000 2012 6 20126
2012-07-01 00:00:00.000 2012 7 20127
2012-08-01 00:00:00.000 2012 8 20128
基础上提出的建议,我的查询现在看起来是这样的:
WITH months AS (
SELECT DateValue, YearMonth FROM Periods_Months('2011-01-01')
)
select m.DateValue
,CAST(DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,m.DateValue)+1,0)) AS Date) AS DateReported -- Get last day in month
,ResponseTime AS Value
,g.ExternalId
from GISDB.dbo.GisObjects g
CROSS JOIN months m
LEFT OUTER JOIN
(-- SELECT data from data table, grouped by area and month
SELECT dbo.YearMonth(CloseDate) AS YearMonth
,MAX(CloseDate) AS LastDate
,GisObjectId
,SUM(DATEDIFF(HH,RegDate,CloseDate)) AS ResponseTime -- calculate response time between start and end data (the value we need)
FROM DataTable
WHERE CloseDate IS NOT NULL
AND GisObjectId IS NOT NULL
GROUP BY GisObjectId, dbo.YearMonth(CloseDate) -- group by area and month
) c
ON g.ObjectId = c.GisObjectId AND c.YearMonth = m.YearMonth
WHERE g.CompanyId = 3 AND g.ObjectTypeId = 1 -- reduce the GIS objects that we compare to
ORDER BY m.DateValue, g.ObjectId
但结果是(值始终为空):
DateValue DateReported Value ExternalId
2011-01-01 00:00:00.000 31-01-2011 NULL 9994
2011-01-01 00:00:00.000 31-01-2011 NULL 9993
2011-01-01 00:00:00.000 31-01-2011 NULL 9992
2011-01-01 00:00:00.000 31-01-2011 NULL 9991
2011-01-01 00:00:00.000 31-01-2011 NULL 2339
2011-01-01 00:00:00.000 31-01-2011 NULL 2338
2011-01-01 00:00:00.000 31-01-2011 NULL 2337
2011-01-01 00:00:00.000 31-01-2011 NULL 2336
2011-01-01 00:00:00.000 31-01-2011 NULL 2335
2011-01-01 00:00:00.000 31-01-2011 NULL 2334
2011-01-01 00:00:00.000 31-01-2011 NULL 2327
2011-01-01 00:00:00.000 31-01-2011 NULL 2326
2011-01-01 00:00:00.000 31-01-2011 NULL 2325
2011-01-01 00:00:00.000 31-01-2011 NULL 2324
2011-01-01 00:00:00.000 31-01-2011 NULL 2323
2011-01-01 00:00:00.000 31-01-2011 NULL 2322
等
哎呀,格式化疯了。希望它仍然是可以理解的... – user1632306
欢迎来到StackOverflow:如果您发布代码,XML或数据样本,请**在文本编辑器中突出显示这些行,然后单击“代码示例”按钮(“{}”)编辑器工具栏可以很好地格式化和语法突出显示它! –
请参阅[编辑帮助](http://stackoverflow.com/editing-help)。 – hims056