这是针对SQL Server 2012的。我被要求优化存储过程，该存储过程用于计算各种发票的账单金额。 这是一个巨大的存储过程，具有多个插入，更新和删除查询，以及对多个表的联接。 存储过程在此特定更新查询上停留了8-9个小时。查询正在更新约400000条记录。

在执行存储过程时，除运行存储过程的连接外，与数据库没有其他连接。

The query is

UPDATE D

SET Amount=CASE WHEN D.Container='PCS' AND DP.AmountPerStop =0 THEN DP1.Amount*IsnULL(IsnULL(M2.MPDFactor,M.MPDFactor),1) ELSE DP1.Amount+DP.Amount*(DeliveryQty-1) END,InvoiceID=I.InvoiceID,MPDFactor=CASE WHEN D.Container='PCS' AND DP.AmountPerStop =0 THEN IsnULL(M2.MPDFactor,M.MPDFactor) ELSE NULL END,PickupAmountCap = DP.PickupAmountCap

FROM dbo.tDeliveries D
   JOIN tDeliveryPrices DP ON DP.ProductGroupCode=D.ProductGroupCode AND DP.Container=D.Container AND DP.Zone=D.Zone
   JOIN tVendorAgreements A ON A.DIP=D.DIP AND DP.VendorAgreementID=A.VendorAgreementID
   JOIN tDeliveryPrices DP1 ON DP1.ProductGroupCode=D.ProductGroupCode AND DP1.Container=D.Container AND DP1.Zone=D.Zone AND DP1.VendorAgreementID=A.VendorAgreementID
   JOIN tDIP DIP ON D.Dip=DIP.Dip
   JOIN tInvoices I ON A.VendorAgreementID=I.VendorAgreementID
   JOIN @tDailyInvoicePeriodForDIP IP ON IP.DIP = DIP.DIP
   LEFT JOIN tMPDFactors M ON M.DIPArea=DIP.DipArea AND M.ProductGroupCode=D.ProductGroupCode AND D.DeliveryQty BETWEEN M.StartQty AND M.EndQty        
   LEFT JOIN tMPDFactors M2 ON M2.DIP=DIP.Dip AND M2.ProductGroupCode=D.ProductGroupCode AND D.DeliveryQty BETWEEN M2.StartQty AND M2.EndQty           

WHERE D.InvoiceID IS NULL AND
      I.InvoicePeriod= @Period AND
      I.InvoiceLockedDate IS NULL AND
      DP1.StartQty=1 AND
      (DeliveryQty BETWEEN DP.StartQty AND DP.EndQty OR D.Container='PCS') AND 
      D.Event_Type = 'I' AND
      @Period BETWEEN A.ValidFromDate AND A.ValidUntilDate

就最终结果而言，查询工作正常。这只花了很多时间。任何帮助将不胜感激。