SQL 查询，使用 COUNT 和 AVERAGES MS SQL Server Management Studio

Question

我对 SQL 还很陌生，请在此查询方面提供一些帮助。到目前为止，这是我的脚本。如果您需要更多信息，请告诉我，

SELECT DISTINCT EstimName_String AS Inspector, InspectionProcedureName AS [Inspection         Procedure Name], COUNT(*) AS InspectionsDone
FROM         UnitData_Vehicle
WHERE     (InspectionProcedureName LIKE '%Inspection%')
where datediff(day, phodat_datetime, getdate()) >= 1
and datediff(day, phodat_datetime, getdate()) <= 4
GROUP BY InspectionProcedureName, EstimName_String
ORDER BY Inspector

但我想看到的是这个。每个检查员每天的总数和平均值，因此 Joe Bloggs 总共进行了 99 次检查，然后将总数平均多少天，即这是 4 天的价值或检查。结果为 24.75。这是可能的？

Inspector   Inspection Procedure Name   Inspections done    Total   Avg per Day
Joe Bloggs  Inspection                        16            99.00   24.75
Joe Bloggs  Inspection                        1     
Joe Bloggs  Inspection                        4     
Joe Bloggs  Inspection                        78        
Jack sprat  Inspection                        14            87.00    21.75
Jack sprat  Inspection                        73        
Humpty Dumpty   Inspection                    7             75.00    18.75
Humpty Dumpty   Inspection                    68        
Micky Mouse Inspection                        13            80.00     20
Micky Mouse Inspection                        67        
Jack Jill   Inspection                        11            76.00     19
Jack Jill   Inspection                        1     
Jack Jill   Inspection                        64        

Answer 1

首先，内部“预查询”每天将获得计数...然后以此为基础来获得总 SUM() 和 AVG()。这将返回每个检查员一行，而不是细分中显示的所有个别日期。

select 
      InspectionProcedureName AS [Inspection         Procedure Name], 
      EstimName_String AS Inspector, 
      sum( InspectionsDone ) as InspectionsDone,
      avg( InspectionsDone ) as AvgInspections
   from 
      ( SELECT 
            InspectionProcedureName, 
            EstimName_String AS Inspector, 
            datediff(day, phodat_datetime, getdate()) as ByDate,
            COUNT(*) AS InspectionsDone
         FROM
            UnitData_Vehicle
         WHERE     
                InspectionProcedureName LIKE '%Inspection%'
            AND datediff(day, phodat_datetime, getdate()) >= 1
            and datediff(day, phodat_datetime, getdate()) <= 4
         GROUP BY 
            InspectionProcedureName, 
            EstimName_String,
            datediff(day, phodat_datetime, getdate()) ) PreQuery
   ORDER BY 
      Inspector

如果你真的想要检查员每天的每一行，你基本上必须添加其他魔法来加入相同的 INNER“PreQuery”以获得单独的一天，真正的魔法只显示总数和平均值每个检查员的第一行。

Answer 2

SELECT EstimName_String AS Inspector, 
InspectionProcedureName AS [Inspection Procedure Name], 
sum(InspectionsDone) AS Total, 
cast(sum(InspectionsDone) as float)/count(*) as [Avg Per Day]
FROM         UnitData_Vehicle
GROUP BY InspectionProcedureName, EstimName_String