Question

我发现查询花了很长时间，因为哈希匹配左连接。 Hash Key probs是

@tempHPDW.DeliveryWMID,@tempHPEng.EngID,Db.METRC.MetMeasure.MeasureId

我读到在这些列上有索引会有所帮助。添加索引后，我应该排序。并将我的表变量更改为临时表。还可以根据这些列进行排序。

查询：

SELECT distinct        
  NISD.EngID,        
  NISD.DeliveryWMID,        
  MEM.MeasureId,          
  1                  
FROM  #Master NISD          
inner join Db.metrc.MetMeasure MEM ON MEM.MetID = nisd.MetID     
LEFT OUTER JOIN 
(SELECT ENG.EngID As EngID,          
     DMU.DeliveryWMID AS DeliveryWMID,          
     MEM.MeasureId AS MeasureID,          
     DMUT.DeliveryMoId  AS DeliveryWMUTypeID   


FROM @tempHPEng ENG          
INNER JOIN Db.DWMU.DeliveryWorkUnit DMUt ON DMUt.EngID = ENG.EngID          
INNER JOIN @tempHPDW DMU ON DMUT.DeliveryWorkUnitId = DMU.DeliveryWMID          
LEFT OUTER JOIN Db.METRC.DeliveryWMScope DS          
ON DS.DeliveryWorkUnitId = DMU.DeliveryWMID          
AND DS.EndPeriodDttm = (select MAX(EndPeriodDttm) from Db.METRC.DeliveryScope           
                 where DeliveryWorkUnitId = DS.DeliveryWorkUnitId           
                 AND MetID = DS.MetID          
                 AND EndPeriodDttm<=@LastReportingWeek)    
LEFT OUTER JOIN Db.METRC.MetMeasure MEM ON MEM.MetID = DS.MetID          
WHERE DS.InScopeInd = 'Y'   ) MIND ON MIND.DeliveryWMID = NISD.DeliveryWMID     
            AND MIND.EngID = NISD.EngID    
            AND MIND.MeasureID = MEM.MeasureId     
where nisd.DeliveryWMID <> -1 AND MIND.MeasureID IS NULL

Answer 1

这可能有效但是你的查询没有意义你正在加入MIND.MeasureID，但后来有一个MIND.MeasureID IS NULL

SELECT distinct NISD.EngID, NISD.DeliveryWMID, MEM.MeasureId, 1                  
  FROM #Master NISD          
  join Db.metrc.MetMeasure MEM 
    ON MEM.MetID = nisd.MetID  
   AND nisd.DeliveryWMID <> -1     
  LEFT OUTER JOIN 
       (  SELECT ENG.EngID As EngID,          
                 DMU.DeliveryWMID AS DeliveryWMID,          
                 MEM.MeasureId AS MeasureID,          
                 DMUT.DeliveryMoId  AS DeliveryWMUTypeID, 
                 rownumber() over (partition by DS.DeliveryWorkUnitId, DS.MetID order by EndPeriodDttm desc) as rowNum 
            FROM @tempHPEng ENG          
            JOIN Db.DWMU.DeliveryWorkUnit DMUt 
              ON DMUt.EngID = ENG.EngID          
            JOIN @tempHPDW DMU 
              ON DMUT.DeliveryWorkUnitId = DMU.DeliveryWMID          
            LEFT OUTER JOIN Db.METRC.DeliveryWMScope DS          
              ON DS.DeliveryWorkUnitId = DMU.DeliveryWMID
             AND EndPeriodDttm<=@LastReportingWeek              
            LEFT OUTER JOIN Db.METRC.MetMeasure MEM 
              ON MEM.MetID = DS.MetID          
           WHERE DS.InScopeInd = 'Y' ) MIND 
    ON MIND.DeliveryWMID = NISD.DeliveryWMID     
   AND MIND.EngID = NISD.EngID    
   AND MIND.MeasureID = MEM.MeasureId   
   AND rownum = 1    
 WHERE MIND.MeasureID IS NULL

如何提高哈希匹配左连接的SQL性能

1 个答案: