Question

如何改善此SQL的执行时间

declare   @Nemo as varchar(30)

set @Nemo = 'TELH14F'

UPDATE Nemos
SET    MPV = px,
       SaleContracts = SC
FROM   (SELECT TOP 1 sum (Qty) SC,
                     Px
        FROM   marketState
        WHERE  Nemo = @Nemo
               AND side = 2
        GROUP  BY Px
        ORDER  BY px) src
WHERE  Nemo = @Nemo

UPDATE Nemos
SET    MPC = px,
       BuyContracts = SC
FROM   (SELECT TOP 1 sum (Qty) SC,
                     Px
        FROM   marketState
        WHERE  Nemo = @Nemo
               AND side = 1
        GROUP  BY Px
        ORDER  BY px DESC) src
WHERE  Nemo = @Nemo

我尝试在同一个表Nemos上合并这两个更新并更改＆＃34;选择前1＆＃34;到MAX或MIN功能没有成功

编辑 - 已添加</ strong>

我还查看了此查询的执行计划，这就是我询问如何改进它的原因

目标是只选择/读取一次MarketState表，并将两个更新合并为一个。

与此类似的东西

update Nemos SET MPV = pxV , SaleContracts =SC, MPC = pxC, BuyContracts =BC FROM (Select top 1 sum (Qty) as SC, px as pxV from marketState where Nemo = @Nemo and side=2 group by Px order by px ) srcA -- UNION ALL-- (Select top 1 sum (Qty) as BC, Px as pxC from marketState where Nemo = @Nemo and side=1 group by Px order by px desc ) srcB where Nemo = @Nemo

如何使用MIN，MAX方法避免使用该UNION或使其工作（请记住列Qty已加总，但列px为不）

这些是表格和指标创作脚本

CREATE TABLE [dbo].[Nemos]( [Nemo] [varchar](50) NOT NULL, [Description] [varchar](50) NULL, [ProductId] [varchar](10) NULL, [ExpirationDate] [datetime] NULL, [CurrentValue] [numeric](21, 5) NULL, [SaleContracts] [int] NULL, [MPV] [numeric](21, 5) NULL, [BuyContracts] [int] NULL, [MPC] [numeric](21, 5) NULL, [Active] [bit] NULL, [ContractQuantity] [numeric](18, 2) NULL, [NemoFactor] [int] NULL, [MinFactor] [numeric](6, 2) NULL, [Factor] [numeric](6, 2) NULL, [Delta] [numeric](6, 2) NULL, [TipoDelta] [varchar](5) NULL, [ContractType] [varchar](50) NULL, [FinalTradingDate] [datetime] NULL, [CompGroup] [varchar](50) NULL, [TypeDelivery] [varchar](5) NULL, [Decimals] [int] NULL, [BeginTradingDate] [datetime] NULL, [PxRef] [numeric](21, 5) NULL, [BuyQty] [int] NULL, [SaleQty] [int] NULL, [LastUpdate] [datetime] NULL ) ON [PRIMARY] GO SET ANSI_PADDING OFF GO ALTER TABLE [dbo].[Nemos] ADD DEFAULT (getdate()) FOR [BeginTradingDate] GO ALTER TABLE [dbo].[Nemos] ADD DEFAULT (getdate()) FOR [LastUpdate] GO /****** TABLE NEMOS INDEXES ******/ CREATE NONCLUSTERED INDEX [Nemos_Nemo] ON [dbo].[Nemos] ( [Nemo] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO /***************************** marketState **************/ CREATE TABLE [dbo].[marketState]( [Nemo] [varchar](50) NULL, [OrderNumber] [varchar](50) NULL, [Px] [numeric](21, 5) NULL, [Qty] [int] NULL, [side] [int] NULL, [owner] [varchar](50) NULL, [LastUpdate] [datetime] NULL, [Consecutivo] [int] IDENTITY(1,1) NOT NULL, CONSTRAINT [PK_marketState] PRIMARY KEY CLUSTERED ( [Consecutivo] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] /****** MARKETSTATE STATE INDEXES ******/ ALTER TABLE [dbo].[marketState] ADD CONSTRAINT [PK_marketState] PRIMARY KEY CLUSTERED ( [Consecutivo] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO CREATE NONCLUSTERED INDEX [Nemo_Side] ON [dbo].[marketState] ( [Nemo] ASC, [side] ASC ) INCLUDE ( [Px], [Qty]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO CREATE NONCLUSTERED INDEX [MS_OrderNumber] ON [dbo].[marketState] ( [OrderNumber] ASC ) INCLUDE ( [owner]) WITH (PAD_INDEX = ON, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 80) ON [PRIMARY] GO

核心思想是计算衍生物的 BestBuyingPrice = MPC 和 BestSellingPrice = MPV （nemo..tecnico）。

当 Side = 1 时，其购买订单，当 Side = 2 时，其 SellingOrder

当两个或多个订单的价格完全相同时，需要添加其数量（总和）见下图

Answer 1

正如我在评论中提到的，检查按行和ASC / DESC子句的顺序是否正确，如果在下面的查询中没有相应更新。

还要确保您有更新的索引

表市场状态：

    CREATE CLUSTERED INDEX CIDX_marketState ON marketState (Px DESC,SIDE ASC,Nemo ASC)

表Nemos：

    CREATE CLUSTERED INDEX CIDX_Nemos ON Nemos (Nemo ASC)

检查以下查询

    update t1 SET  
        MPV = pxV
        ,SaleContracts =SC
        ,MPC = pxC
        ,BuyContracts =BC
    FROM
    Nemos  t1
    JOIN
    (
        Select TOP 1 sum (Qty) as SC, px as pxV, @Nemo AS Nemo
        from marketState 
        where Nemo = @Nemo and side=2 
        group by Px
        ORDER BY px DESC    
    ) srcA
    ON srcA.Nemo=t1.Nemo
    JOIN
    (
        Select TOP 1 sum (Qty) as BC, Px as pxC, @Nemo AS Nemo
        from marketState 
        where Nemo = @Nemo and side=1 
        group by Px 
        order by px desc 
    ) srcB
        ON srcA.Nemo = srcB.Nemo

修改：1 因为OP询问是否可以在单个读取和单个更新中执行此查询。但我不认为与上述相比，性能会有很大差异。

上面提到的相同索引也适用于此查询。

update t1 SET MPV = q2.MPV ,SaleContracts =q2.SaleContracts ,MPC = q2.MPC ,BuyContracts =q2.BuyContracts FROM Nemos t1 JOIN ( SELECT SUM(CASE WHEN q1.side = 2 THEN q1.px END) AS MPV ,SUM(CASE WHEN q1.side=2 THEN q1.qty END) AS SaleContracts ,SUM(CASE WHEN q1.side=1 THEN px END) AS MPC ,SUM(CASE WHEN q1.side=1 THEN qty END) AS BuyContracts ,@Nemo AS Nemo FROM ( SELECT sum (Qty) as Qty,px,Side ,ROW_NUMBER() OVER (PARTITION BY side ORDER BY Px Desc) AS RowID from marketState where Nemo = @Nemo AND side IN (1,2) group by Px,Side )q1 WHERE q1.RowID=1 )q2 ON t1.nemo=q2.Nemo

Answer 2

如果目标是只读取一次MarketState表，那么我将在一个查询中计算您的两个值，并将这些结果放在临时表中。然后，您可以使用临时表在Nemos表上执行UPDATE。

像这样......

    SELECT Px, Side, SUM(Qty) SC
    INTO #Results
    FROM   marketState
    WHERE  Nemo = @Nemo               
    GROUP  BY Px, Side


    UPDATE Nemos
    SET    MPV = px,
           SaleContracts = SC
    FROM   (SELECT TOP 1 (Qty) SC,
                         Px
            FROM   #Results
            WHERE side = 2
            ORDER  BY Qty) src
    WHERE  Nemo = @Nemo 

    UPDATE Nemos
    SET    MPC = px,
           SaleContracts = SC
    FROM   (SELECT TOP 1 (Qty) SC,
                         Px
            FROM   #Results
            WHERE side = 1
            ORDER  BY Qty) src
    WHERE  Nemo = @Nemo

请告知我如何改善此SQL的执行时间

2 个答案: