填充事实表数据仓库和查询

如何解决填充事实表数据仓库和查询

我不确定如何查询我的事实表（covid 和疫苗接种），我用虚拟数据填充了维度，我应该将事实表留空？据我所知，当我编写查询时，它们会被填充。

我不知道如何查询我尝试过的不同的表，但我得到了一个空的结果。 下面是架构的链接。 我想找出由每个“菌株”引起的去年的“TotalDeathsUK”（事实表 COVID）（我的菌株表共有 3 个菌株。

解决方法

您可以使用 MERGE 填充事实表 COVIDFact :

MERGE 
INTO         factcovid 
using        ( 
                    SELECT centerid,dateid,patientid,strainid 
                    FROM   yourstagingfacttable ) AS f 
ON factcovid.centerid = f.centerid AND factcovid.dateid=f.dateid... //the join columns
WHEN matched THEN 
do nothing WHEN NOT matched THEN 
INSERT VALUES 
       ( 
              f.centerid,f.dateid,f.patientid,f.strainid 
       )

对于VaccinationsFact：

MERGE 
INTO         vaccinations 
using        ( 
                    SELECT centerid,vaccineid 
                    FROM   yourstagingfacttable ) AS f 
ON factcovid.centerid = f.centerid //join condition(s) 
WHEN matched THEN 
do nothing WHEN NOT matched THEN 
INSERT VALUES 
       ( 
              f.centerid,f.vaccineid 
       )

对于 TotalDeathUK 度量：

SELECT S.[Name] AS Strain,COUNT(CF.PatientID) AS [Count of Deaths] FROM CovidFact AS CF
    LEFT JOIN Strain AS S ON S.StrainID=CF.StrainID
    LEFT JOIN Time AS T ON CF.DateID=T.DateID
    LEFT JOIN TreatmentCenter AS TR ON TR.CenterID=CF.CenterID
    LEFT JOIN City AS C ON C.CityID = TR.CityID
    WHERE C.Country LIKE 'UK' AND T.Year=2020
    AND Result LIKE 'Death' // you should add a Result column to check if the Patient survived or died
    GROUP BY S.[Name]