SQLでスカラー関数のパフォーマンスを向上させるにはどうすればよいですか？

Question

私のテーブルビューでは、私は4スカラー関数を呼び出す必要があります。 例：

CREATE view [SUMMARY] 
AS 

SELECT [Code] , 
    ... 
    dbo.[udf_REPORTTYPE](ts.LegTankSystemId,ReportingDate,analysis.[AnalysisTypeName]) as ReportingType , 
    dbo.[udf_WATER](ts.SystemId,LastObsDate) as WaterReading, 
    case when analysis.LastObsDate is null then NULL else dbo.[udf_BJs_GENERAL](ts.LegTankSystemId,ISNULL(analysis.LastObsDate, ssd.ReportingDate)) end as [1Plus130_Reslut], 
    (CASE WHEN State ='NY' THEN dbo.[udf_NY](ts.SystemId,LastObsDate) 
     WHEN State ='CT' THEN dbo.[udf_CT] (ts.SystemId,LastObsDate) 
    END) AS State_SIR_Result 
FROM LOBDW.SITE dimsite 
LEFT JOIN [bjs].[udv_TANK] ts on dimsite.SiteId = ts.SiteId 

...

私は同じパラメータを読み込み、異なる計算を行って、これらのスカラー関数で。

私の見解は、1分以上かかります400行を返すように。それは本当に悪いです。 これらのスカラー関数のパフォーマンスを改善することはできますか？ある関数からグローバル変数を定義し、両方の関数が同じデータを必要とする場合、その関数を別の関数で使用する方法はありますか？

例えば機能。

CREATE FUNCTION [dbo].[udf_REPORTTYPE] 
    (
     @TankSystemId int, 
     @TimeStamp datetime2(7), 
     @AnalysisTypeName varchar(10) 
    ) 
RETURNS varchar(10) 
AS 
BEGIN 
    DECLARE @ReportType varchar(10); 
    DECLARE @TimePeriod datetime2(7) 
    DECLARE @LatestAnalysisDate datetime2(7) 

    SELECT TOP 1 @TimePeriod = Date FROM udv_DailySiraData where TankSystemId=@TankSystemId ORDER BY Date DESC 
    SELECT TOP 1 @LatestAnalysisDate = LastObsDate FROM [udv_ANALYSES] where TankSystemId =@TankSystemId ORDER BY LastObsDate DESC 

    SET @ReportType=@AnalysisTypeName 
    IF ((@TimePeriod>=@TimeStamp) AND (@LatestAnalysisDate < @TimeStamp) AND @AnalysisTypeName IS NULL) 
     SET @ReportType = 'No Analysis Result'; 
    IF ((@TimePeriod>=@TimeStamp) AND @AnalysisTypeName IS NULL) 
     SET @ReportType = 'Latest'; 

    RETURN @ReportType; 
END; 

Answer 1

あなたはOUTERへのあなたのUDFが適用変換することができ、この

SELECT [Code] , 
    ... 
    --dbo.[udf_REPORTTYPE](ts.LegTankSystemId,ReportingDate,analysis.[AnalysisTypeName]) as ReportingType , -- change from UDF to Outer Apply 
    RT.ReportingType, 
    dbo.[udf_WATER](ts.SystemId,LastObsDate) as WaterReading, 
    case when analysis.LastObsDate is null then NULL else dbo.[udf_BJs_GENERAL](ts.LegTankSystemId,ISNULL(analysis.LastObsDate, ssd.ReportingDate)) end as [1Plus130_Reslut], 
    (CASE WHEN State ='NY' THEN dbo.[udf_NY](ts.SystemId,LastObsDate) 
     WHEN State ='CT' THEN dbo.[udf_CT] (ts.SystemId,LastObsDate) 
    END) AS State_SIR_Result 
FROM LOBDW.SITE dimsite 
    LEFT JOIN [bjs].[udv_TANK] ts on dimsite.SiteId = ts.SiteId 
    OUTER APPLY -- convert from udf_REPORTTYPE 
    (
     SELECT ReportingType = 
       CASE WHEN MAX(x.DATE) >= ssd.ReportingDate 
         AND  MAX(y.LastObsDate) < ssd.ReportingDate 
         AND  analysis.[AnalysisTypeName] iS NULL 
         THEN 'No Analysis Result' 
         WHEN MAX(x.DATE) >= ssd.ReportingDate 
         AND  analysis.[AnalysisTypeName] iS NULL 
         THEN 'Latest' 
         ELSE analysis.[AnalysisTypeName] 
         END 
     FROM udv_DailySiraData x 
      INNER JOIN udv_ANALYSES y ON x.TankSystemId = y.TankSystemId 
     WHERE x.TankSystemId = ts.LegTankSystemId 
    ) RT 

Answer 2

私は正常に動作していると確信しているが、ここでは適用さOUTERへのCTEの代替は、だような何か...

WITH TimePeriods AS (
    SELECT 
     TankSystemId, 
     TimePeriod = MAX(Date) 
    FROM 
     udv_DailySiraData 
    GROUP BY 
     TankSystemId 
), AnalysisDates AS (
    SELECT 
     TankSystemId, 
     LatestAnalysisDate = MAX(LastObsDate) 
    FROM 
     udv_ANALYSES 
    GROUP BY 
     TankSystemId 
) 
SELECT 
    ... 
    ReportingType = 
     CASE 
      WHEN tp.TimePeriod >= ReportingDate AND ad.LatestAnalysisDate < ReportingDate AND analysis.AnalysisTypeName IS NULL THEN 'No Analysis Result' 
      WHEN tp.TimePeriod >= ReportingDate AND analysis.AnalysisTypeName IS NULL THEN 'Latest' 
      ELSE analysis.AnalysisTypeName 
     END, 
    ... 
FROM 
    LOBDW.SITE dimsite 
LEFT JOIN 
    bjs.udv_TANK ts 
    ON dimsite.SiteId = ts.SiteId 
LEFT JOIN 
    TimePeriods tp 
    ON ts.LegTankSystemId = tp.TankSystemId 
LEFT JOIN 
    AnalysisDates ad 
    ON ts.LegTankSystemId = tp.TankSystemId