实战：上亿数据如何秒查

转：http://www.cnblogs.com/hangwei/p/4399238.html

最近在忙着优化集团公司的一个报表。优化完成后，报表查询速度有从半小时以上(甚至查不出)到秒查的质变。从修改SQL查询语句逻辑到决定创建存储

过程实现，花了我3天多的时间，在此总结一下，希望对朋友们有帮助。

数据背景

首先项目是西门子中国在我司实施部署的MES项目，由于项目是在产线上运作(3 years+)，数据累积很大。在项目的数据库中，大概上亿条数据的表有5个以上，千万级数据的表10个以上，百万级数据的表，很多...

(历史问题，当初实施无人监管，无人监控数据库这块的性能问题。ps:我刚入职不久...)

不多说，直接贴西门子中国的开发人员在我司开发的SSRS报表中的SQL语句：

select distinct b.MaterialID as matl_def_id, c.Descript, case when right(b.MESOrderID, 12) < '001000000000' then right(b.MESOrderID, 9)  
else right(b.MESOrderID, 12) end  as pom_order_id, a.LotName, a.SourceLotName as ComLot, 
e.DefID as ComMaterials, e.Descript as ComMatDes, d.VendorID, d.DateCode,d.SNNote, b.OnPlantID,a.SNCUST
from  
(
    select m.lotname, m.sourcelotname, m.opetypeid, m.OperationDate,n.SNCUST from View1 m
    left join co_sn_link_customer as n on n.SNMes=m.LotName
    where 
    ( m.LotName in (select val from fn_String_To_Table(@sn,',',1)) or (@sn) = '') and 
    ( m.sourcelotname in (select val from fn_String_To_Table(@BatchID,',',1)) or (@BatchID) = '')
    and (n.SNCust like '%'+ @SN_ext + '%' or (@SN_ext)='')
) a
left join 
(
    select * from Table1 where SNType = 'IntSN'
    and SNRuleName = 'ProductSNRule'
    and OnPlantID=@OnPlant
) b on b.SN = a.LotName
inner join MMdefinitions as c on c.DefID = b.MaterialID
left join  Table1 as d on d.SN = a.SourceLotName 
inner join MMDefinitions as e on e.DefID = d.MaterialID
where not exists (
 select distinct LotName, SourceLotName from ELCV_ASSEMBLE_OPS 
where LotName = a.SourceLotName and SourceLotName = a.LotName
) 
and (d.DateCode in (select val from fn_String_To_Table(@DCode,',',1)) or (@DCode) = '')
and (d.SNNote  like '%'+@SNNote+'%' or (@SNNote) = '')
and ((case when right(b.MESOrderID, 12) < '001000000000' then right(b.MESOrderID, 9)  
else right(b.MESOrderID, 12) end) in (select val from fn_String_To_Table(@order_id,',',1)) or (@order_id) = '')
and (e.DefID in (select val from fn_String_To_Table(@comdef,',',1)) or (@comdef) = '')
--View1是一个嵌套两层的视图(出于保密性，实际名称可能不同)，里面有一张上亿数据的表和几张千万级数据的表做左连接查询
--Table1是一个数据记录超过1500万的表

这个查询语句，实际上通过我的检测和调查，在B/S系统前端已无法查出结果，半小时，一小时 ... 。因为我直接在SQL查询分析器查，半小时都没有结果。

(原因是里面对一张上亿级数据表和3张千万级数据表做全表扫描查询)

不由感慨，西门子中国的素质(或者说责任感)就这样？

下面说说我的分析和走的弯路(思维误区)，希望对你也有警醒。

探索和误区

首先相关表的索引，没有建全的，把索引给建上。

索引这步完成后，发现情况还是一样，查询速度几乎没有改善。后来想起相关千万级数据以上的表，都还没有建立表分区。于是考虑建立表分区以及数据复制的方案。

这里有必要说明下：我司报表用的是一个专门的数据库服务器，数据从产线订阅而来。就是常说的“读写分离”。

如果直接在原表上建立表分区，你会发现执行表分区的事物会直接死锁。原因是：表分区操作本身会锁表，产线还在推数据过来，这样很容易“阻塞”，“死锁”。

我想好的方案是：建立一个新表(空表)，在新表上建好表分区，然后复制数据过来。

正打算这么干。等等！我好像进入了一个严重的误区！

分析： 原SQL语句和业务需求，是对产线的数据做产品以及序列号的追溯，关键是查询条件里没有有规律的"条件"(如日期、编号)，

         贸然做了表分区，在这里几乎没有意义！反而会降低查询性能！

好险！还是一步一步来，先做SQL语句分析。

一. 对原SQL语句的分析

1. 查询语句的where条件，有大量@var in ... or (@var ='') 的片段

2. where条件有like '%'+@var+'%' 

3. where条件有 case ... end 函数

4. 多次连接同一表查询，另外使用本身已嵌套的视图表，是不是必须，是否可替代？

5. SQL语句有*号，视图中也有*号出现

二. 优化设计

首先是用存储过程改写，好处是设计灵活。

核心思想是：用一个或多个查询条件(查询条件要求至少输入一个)得到临时表，每个查询条件如果查到集合，就更新这张临时表，最后汇总的时候，

                 只需判断这个临时表是否有值。以此类推，可以建立多个临时表，将查询条件汇总。

这样做目前来看至少两点好处：1.省去了对变量进行 =@var or (@var='')的判断；

                                        2.抛弃sql拼接，提高代码可读性。

再有就是在书写存储过程，这个过程中要注意：

1. 尽量想办法使用临时表扫描替代全表扫描；

2. 抛弃in和not in语句，使用exists和not exists替代；

3. 和客户确认，模糊查询是否有必要，如没有必要，去掉like语句；

4. 注意建立适当的，符合场景的索引；

5. 踩死 "*" 号；

6. 避免在where条件中对字段进行函数操作；

7. 对实时性要求不高的报表，允许脏读(with(nolock))。

三. 存储过程

如果想参考优化设计片段的详细内容，请参阅SQL代码：

/**
 * 某某跟踪报表
 **/
--exec spName1 '','','','','','','公司代号'
CREATE Procedure spName1
   @MESOrderID nvarchar(320), --工单号,最多30个
   @LotName nvarchar(700),    --产品序列号,最多50个
   @DateCode nvarchar(500),   --供应商批次号,最多30个
   @BatchID nvarchar(700),    --组装件序列号/物料批号,最多50个
   @comdef nvarchar(700),     --组装件物料编码,最多30个
   @SNCust nvarchar(1600),    --外部序列号,最多50个
   @OnPlant nvarchar(20)      --平台
AS
BEGIN
    SET NOCOUNT ON;  
    /**
     * 1)定义全局的临时表，先根据六个查询条件的任意一个，得出临时表结果
     **/
    CREATE TABLE #FinalLotName
    (
        LotName NVARCHAR(50),       --序列号
        SourceLotName NVARCHAR(50), --来源序列号
        SNCust NVARCHAR(128)        --外部序列号
    )
    --1.1
    IF @LotName<>''
    BEGIN
        SELECT Val INTO #WorkLot FROM fn_String_To_Table(@LotName,',',1)
        SELECT LotPK,LotName INTO #WorkLotPK FROM MMLots WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLot b WHERE b.Val=MMLots.LotID)
        
        --求SourceLotPK只能在这里求
        SELECT a.LotPK,a.SourceLotPK into #WorkSourcePK FROM MMLotOperations a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLotPK b WHERE b.LotPK=a.LotPK) AND a.SourceLotPK IS NOT NULL
        
        SELECT a.LotPK,a.SourceLotPK,b.LotName INTO #WorkSourcePK2 FROM #WorkSourcePK a JOIN #WorkLotPK b ON a.LotPK=b.LotPK
        
        INSERT INTO #FinalLotName SELECT a.LotName,b.LotName AS SourceLotName,NULL FROM #WorkSourcePK2 a JOIN (SELECT LotPK,LotName FROM MMLots WITH(NOLOCK) ) b on a.SourceLotPK=b.LotPK --b的里面加不加WHERE RowDeleted=0待确定
        SELECT a.LotName,a.SourceLotName,b.SNCust INTO #FinalLotNameX1 FROM #FinalLotName a LEFT JOIN CO_SN_LINK_CUSTOMER b WITH(NOLOCK) ON a.LotName=b.SNMes
        DELETE FROM #FinalLotName
        INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX1
    END
    --1.2
    IF @BatchID<>''
    BEGIN
        SELECT Val INTO #WorkSourceLot FROM fn_String_To_Table(@BatchID,',',1)
        IF EXISTS(SELECT 1 FROM #FinalLotName)--如果@LotName也不为空
        BEGIN
            SELECT a.LotName,a.SourceLotName,a.SNCust INTO #FinalLotNameX2 FROM #FinalLotName a WHERE EXISTS(SELECT 1 FROM #WorkSourceLot b WHERE a.SourceLotName=b.Val)
            DELETE FROM #FinalLotName
            INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX2
        END
        ELSE --@LotName条件为空
        BEGIN
            SELECT LotPK AS SourceLotPK,LotName AS SourceLotName INTO #2 FROM MMLots WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkSourceLot b WHERE b.Val=MMLots.LotID)
            SELECT a.LotPK,a.SourceLotPK into #21 FROM MMLotOperations a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #2 b WHERE b.SourceLotPK=a.SourceLotPK)
            SELECT a.LotPK,a.SourceLotPK,b.SourceLotName INTO #22 FROM #21 a JOIN #2 b ON a.SourceLotPK=b.SourceLotPK    
            INSERT INTO #FinalLotName SELECT b.LotName,a.SourceLotName,NULL FROM #22 a JOIN (SELECT LotPK,LotName FROM MMLots WITH(NOLOCK) ) b on a.LotPK=b.LotPK --b的里面加不加WHERE RowDeleted=0待确定    
            SELECT a.LotName,a.SourceLotName,b.SNCust INTO #FinalLotNameX21 FROM #FinalLotName a LEFT JOIN CO_SN_LINK_CUSTOMER b WITH(NOLOCK) ON a.LotName=b.SNMes
            DELETE FROM #FinalLotName
            INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX21        
        END
    END
    --1.3
    IF @SNCust<>''
    BEGIN
        SELECT Val INTO #WorkCustomSN FROM fn_String_To_Table(@SNCust,',',1)
        IF EXISTS(SELECT 1 FROM #FinalLotName)--前面两个条件至少有一个有值
        BEGIN
            SELECT a.LotName,a.SourceLotName,a.SNCust INTO #FinalLotNameX3 FROM #FinalLotName a WHERE EXISTS(SELECT 1 FROM #WorkCustomSN b WHERE a.SNCust=b.Val)
            DELETE FROM #FinalLotName 
            INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX3
        END
        ELSE
        BEGIN
            SELECT a.SNMes INTO #WorkLotX FROM CO_SN_LINK_CUSTOMER a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkCustomSN b WHERE a.SNCust=b.Val)
            -------------------以下逻辑和变量1(@LotName)类似[先根据外部序列号求解序列号,再照搬第一个判断变量的方式]
            SELECT LotPK,LotName INTO #WorkLotPKX FROM MMLots WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLotX b WHERE b.SNMes=MMLots.LotID)
        
            --求SourceLotPK只能在这里求
            SELECT a.LotPK,a.SourceLotPK into #WorkSourcePKX FROM MMLotOperations a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLotPKX b WHERE b.LotPK=a.LotPK) AND a.SourceLotPK IS NOT NULL
            
            SELECT a.LotPK,a.SourceLotPK,b.LotName INTO #WorkSourcePK2X FROM #WorkSourcePKX a JOIN #WorkLotPKX b ON a.LotPK=b.LotPK
            
            INSERT INTO #FinalLotName SELECT a.LotName,b.LotName AS SourceLotName,NULL FROM #WorkSourcePK2X a JOIN (SELECT LotPK,LotName FROM MMLots WITH(NOLOCK) ) b on a.SourceLotPK=b.LotPK --b的里面加不加WHERE RowDeleted=0待确定
            SELECT a.LotName,a.SourceLotName,b.SNCust INTO #FinalLotNameX31 FROM #FinalLotName a LEFT JOIN CO_SN_LINK_CUSTOMER b WITH(NOLOCK) ON a.LotName=b.SNMes
            DELETE FROM #FinalLotName
            INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX31
            -----------------------
        END
    END
    
    /**
     * 2)定义全局的临时表，用于替换第一个全局临时表。
     **/
    CREATE TABLE #FinalCO_SN
    (
        SN NVARCHAR(50),
        SourceSN NVARCHAR(50),
        SNCust NVARCHAR(128),
        matl_def_id NVARCHAR(50),--sn的物料ID
        ComMaterials NVARCHAR(50),  --SourceSN的物料ID
        MESOrderID NVARCHAR(20),
        OnPlantID NVARCHAR(20),
        VendorID NVARCHAR(20),
        DateCode NVARCHAR(20) ,
        SNNote NVARCHAR(512)
    )
    --2.1
    IF @MESOrderID<>''
    BEGIN
        -------------------------------将MESOrderID做特殊处理-----------------------------------
        SELECT Val INTO #WorkMESOrderID FROM fn_String_To_Table(@MESOrderID,',',1)
        IF @OnPlant='Comba'
        BEGIN
            UPDATE #WorkMESOrderID SET Val='C000'+Val WHERE LEN(Val)=9
        END
        ELSE
        BEGIN
            UPDATE #WorkMESOrderID SET Val='W000'+Val WHERE LEN(Val)=9
        END
        SELECT SN,MaterialID,MESOrderID,OnPlantID INTO #WorkCO_SN1 FROM CO_SN_GENERATION a WITH(NOLOCK)
        WHERE SNType='IntSN' AND SNRuleName = 'ProductSNRule' AND OnPlantID=@OnPlant
        AND EXISTS(SELECT 1 FROM #WorkMESOrderID b WHERE a.MESOrderID=b.Val)
        ------------------------------------------------------------------------------------------
        --条件判断(逻辑分析)开始
        IF EXISTS(SELECT 1 FROM #FinalLotName)--如果前面判断的查询条件有值
        BEGIN
            --查出SourceLotName对应的查询字段
            SELECT a.SN AS SourceLotName,a.VendorID,a.DateCode,a.SNNote,a.MaterialID AS ComMaterials INTO #SourceLotNameTable FROM CO_SN_GENERATION a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.SourceLotName)
            
            INSERT INTO #FinalCO_SN
            SELECT a.LotName,a.SourceLotName,d.SNCust,b.MaterialID,c.ComMaterials,b.MESOrderID,b.OnPlantID,c.VendorID,c.DateCode,c.SNNote FROM #FinalLotName a 
            LEFT JOIN #WorkCO_SN1 b ON a.LotName=b.SN
            LEFT JOIN #SourceLotNameTable c ON a.SourceLotName=c.SourceLotName
            LEFT JOIN CO_SN_LINK_CUSTOMER d WITH(NOLOCK) ON a.LotName=d.SNMes
        END
        ELSE
        BEGIN
            --已知SN集合求解对应的SourceSN和SNCust集合------------------------------------------
            SELECT LotPK,LotName INTO #WorkLotPK410 FROM MMLots WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkCO_SN1 b WHERE b.SN=MMLots.LotID)
            SELECT a.LotPK,a.SourceLotPK into #WorkSourcePK420 FROM MMLotOperations a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLotPK410 b WHERE b.LotPK=a.LotPK) AND a.SourceLotPK IS NOT NULL
            SELECT a.LotPK,a.SourceLotPK,b.LotName INTO #WorkSourcePK430 FROM #WorkSourcePK420 a JOIN #WorkLotPK410 b ON a.LotPK=b.LotPK
            INSERT INTO #FinalLotName SELECT a.LotName,b.LotName AS SourceLotName,NULL FROM #WorkSourcePK430 a JOIN (SELECT LotPK,LotName FROM MMLots WITH(NOLOCK) ) b on a.SourceLotPK=b.LotPK --b的里面加不加WHERE RowDeleted=0待确定
            
            SELECT a.LotName,a.SourceLotName,b.SNCust INTO #FinalLotNameX440 FROM #FinalLotName a LEFT JOIN CO_SN_LINK_CUSTOMER b WITH(NOLOCK) ON a.LotName=b.SNMes
            DELETE FROM #FinalLotName
            INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #FinalLotNameX440
            -------------------------------------------------------------------------------------
            SELECT a.SN AS SourceLotName,a.VendorID,a.DateCode,a.SNNote,a.MaterialID AS ComMaterials INTO #SourceLotNameTable2 FROM CO_SN_GENERATION a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.SourceLotName)
            
            INSERT INTO #FinalCO_SN
            SELECT a.LotName,a.SourceLotName,a.SNCust,b.MaterialID,c.ComMaterials,b.MESOrderID,b.OnPlantID,c.VendorID,c.DateCode,c.SNNote FROM #FinalLotName a 
            LEFT JOIN #WorkCO_SN1 b ON a.LotName=b.SN
            LEFT JOIN #SourceLotNameTable2 c ON a.SourceLotName=c.SourceLotName
        END    
    END
    --2.2
    IF @DateCode<>''
    BEGIN
        SELECT Val INTO #WorkDateCode FROM fn_String_To_Table(@DateCode,',',1)
        --此@DataCode条件求解出来的是SourceSN
        SELECT SN AS SourceSN,MaterialID AS ComMaterials,VendorID,DateCode,SNNote INTO #WorkSourceSNT1 FROM CO_SN_GENERATION a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkDateCode b WHERE a.DateCode=b.Val)
        ----------------------------------------------------------------------------------------------------
        --条件判断(逻辑分析)开始
        IF EXISTS(SELECT 1 FROM #FinalCO_SN)--如果前面判断的查询条件有值
        BEGIN
            SELECT a.LotName,a.SourceLotName,a.SNCust,a.MaterialID,a.ComMaterials,a.MESOrderID,a.OnPlantID,a.VendorID,a.DateCode,a.SNNote INTO #TMP51 FROM #FinalCO_SN a WHERE EXISTS (SELECT 1 FROM #WorkDateCode b WHERE a.DateCode=b.Val)
            DELETE FROM #FinalCO_SN
            INSERT INTO #FinalCO_SN SELECT LotName,SourceLotName,SNCust,MaterialID,ComMaterials,MESOrderID,OnPlantID,VendorID,DateCode,SNNote FROM #TMP51
        END
        ELSE
        BEGIN
            IF EXISTS(SELECT 1 FROM #FinalLotName)
            BEGIN
            --查出SourceLotName对应的查询字段
            SELECT a.SourceSN,a.VendorID,a.DateCode,a.SNNote,a.ComMaterials INTO #SourceLTX5 FROM #WorkSourceSNT1 a WHERE EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SourceSN=b.SourceLotName)
            --查出SN对应的查询字段
            SELECT SN,MaterialID,MESOrderID,OnPlantID INTO #WorkSNT510 FROM CO_SN_GENERATION a WITH(NOLOCK)
            WHERE SNType='IntSN' AND SNRuleName = 'ProductSNRule' AND OnPlantID=@OnPlant
            AND EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.LotName)
            
            INSERT INTO #FinalCO_SN
            SELECT a.LotName,a.SourceLotName,d.SNCust,b.MaterialID,c.ComMaterials,b.MESOrderID,b.OnPlantID,c.VendorID,c.DateCode,c.SNNote FROM #FinalLotName a 
            LEFT JOIN #WorkSNT510 b ON a.LotName=b.SN
            LEFT JOIN #WorkSourceSNT1 c ON a.SourceLotName=c.SourceSN
            LEFT JOIN CO_SN_LINK_CUSTOMER d WITH(NOLOCK) ON a.LotName=d.SNMes
            
            END
            ELSE
            BEGIN
                --已知SourceSN集合求解对应的SN和SNCust集合------------------------------------------
                SELECT LotPK AS SourceLotPK,LotName AS SrouceLotName INTO #WorkLotX510 FROM MMLots WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkSourceSNT1 b WHERE b.SourceSN=MMLots.LotID)
                SELECT a.LotPK,a.SourceLotPK into #WorkLotX520 FROM MMLotOperations a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLotX510 b WHERE b.SourceLotPK=a.SourceLotPK)
                SELECT a.LotPK,a.SourceLotPK,b.SrouceLotName INTO #WorkLotX530 FROM #WorkLotX520 a JOIN #WorkLotX510 b ON a.SourceLotPK=b.SourceLotPK
                
                INSERT INTO #FinalLotName SELECT b.LotName,a.SrouceLotName,NULL FROM #WorkLotX530 a JOIN (SELECT LotPK,LotName FROM MMLots WITH(NOLOCK) ) b on a.LotPK=b.LotPK --b的里面加不加WHERE RowDeleted=0待确定
                
                SELECT a.LotName,a.SourceLotName,b.SNCust INTO #WorkLotX540 FROM #FinalLotName a LEFT JOIN CO_SN_LINK_CUSTOMER b WITH(NOLOCK) ON a.LotName=b.SNMes
                DELETE FROM #FinalLotName
                INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #WorkLotX540
                -------------------------------------------------------------------------------------
                SELECT SN,MaterialID,MESOrderID,OnPlantID INTO #WorkLotX550 FROM CO_SN_GENERATION a WITH(NOLOCK)
                WHERE SNType='IntSN' AND SNRuleName = 'ProductSNRule' AND OnPlantID=@OnPlant
                AND EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.LotName)
            
                INSERT INTO #FinalCO_SN
                SELECT a.LotName,a.SourceLotName,a.SNCust,b.MaterialID,c.ComMaterials,b.MESOrderID,b.OnPlantID,c.VendorID,c.DateCode,c.SNNote FROM #FinalLotName a 
                LEFT JOIN #WorkLotX550 b ON a.LotName=b.SN
                LEFT JOIN #WorkSourceSNT1 c ON a.SourceLotName=c.SourceSN
            END
        END
    END
    --2.3
    IF @comdef<>''
    BEGIN
        SELECT Val INTO #WorkComdef FROM fn_String_To_Table(@comdef,',',1)
        --此@comdef条件求解出来的是SourceSN
        SELECT SN AS SourceSN,MaterialID AS ComMaterials,VendorID,DateCode,SNNote INTO #WorkSourceSNT16 FROM CO_SN_GENERATION a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkComdef b WHERE a.MaterialID=b.Val)
        ----------------------------------------------------------------------------------------------------
        --条件判断(逻辑分析)开始
        IF EXISTS(SELECT 1 FROM #FinalCO_SN)--如果前面判断的查询条件有值
        BEGIN
            SELECT a.LotName,a.SourceLotName,a.SNCust,a.MaterialID,a.ComMaterials,a.MESOrderID,a.OnPlantID,a.VendorID,a.DateCode,a.SNNote INTO #TMP516 FROM #FinalCO_SN a WHERE EXISTS (SELECT 1 FROM #WorkComdef b WHERE a.matl_def_id=b.Val)
            DELETE FROM #FinalCO_SN
            INSERT INTO #FinalCO_SN SELECT LotName,SourceLotName,SNCust,MaterialID,ComMaterials,MESOrderID,OnPlantID,VendorID,DateCode,SNNote FROM #TMP516
        END
        ELSE
        BEGIN
            IF EXISTS(SELECT 1 FROM #FinalLotName)
            BEGIN
            --查出SourceLotName对应的查询字段
            SELECT a.SourceSN,a.VendorID,a.DateCode,a.SNNote,a.ComMaterials INTO #SourceLTX56 FROM #WorkSourceSNT16 a WHERE EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SourceSN=b.SourceLotName)
            --查出SN对应的查询字段
            SELECT SN,MaterialID,MESOrderID,OnPlantID INTO #WorkSNT5106 FROM CO_SN_GENERATION a WITH(NOLOCK)
            WHERE SNType='IntSN' AND SNRuleName = 'ProductSNRule' AND OnPlantID=@OnPlant
            AND EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.LotName)
            
            INSERT INTO #FinalCO_SN
            SELECT a.LotName,a.SourceLotName,d.SNCust,b.MaterialID,c.ComMaterials,b.MESOrderID,b.OnPlantID,c.VendorID,c.DateCode,c.SNNote FROM #FinalLotName a 
            LEFT JOIN #WorkSNT5106 b ON a.LotName=b.SN
            LEFT JOIN #WorkSourceSNT16 c ON a.SourceLotName=c.SourceSN
            LEFT JOIN CO_SN_LINK_CUSTOMER d WITH(NOLOCK) ON a.LotName=d.SNMes
            
            END
            ELSE
            BEGIN
                --已知SourceSN集合求解对应的SN和SNCust集合------------------------------------------
                SELECT LotPK AS SourceLotPK,LotName AS SrouceLotName INTO #WorkLotX5106 FROM MMLots WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkSourceSNT16 b WHERE b.SourceSN=MMLots.LotID)
                SELECT a.LotPK,a.SourceLotPK into #WorkLotX5206 FROM MMLotOperations a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #WorkLotX5106 b WHERE b.SourceLotPK=a.SourceLotPK)
                SELECT a.LotPK,a.SourceLotPK,b.SrouceLotName INTO #WorkLotX5306 FROM #WorkLotX5206 a JOIN #WorkLotX5106 b ON a.SourceLotPK=b.SourceLotPK
                
                INSERT INTO #FinalLotName SELECT b.LotName,a.SrouceLotName,NULL FROM #WorkLotX5306 a JOIN (SELECT LotPK,LotName FROM MMLots WITH(NOLOCK) ) b on a.LotPK=b.LotPK --b的里面加不加WHERE RowDeleted=0待确定
                
                SELECT a.LotName,a.SourceLotName,b.SNCust INTO #WorkLotX5406 FROM #FinalLotName a LEFT JOIN CO_SN_LINK_CUSTOMER b WITH(NOLOCK) ON a.LotName=b.SNMes
                DELETE FROM #FinalLotName
                INSERT INTO #FinalLotName SELECT LotName,SourceLotName,SNCust FROM #WorkLotX5406
                -------------------------------------------------------------------------------------
                SELECT SN,MaterialID,MESOrderID,OnPlantID INTO #WorkLotX5506 FROM CO_SN_GENERATION a WITH(NOLOCK)
                WHERE SNType='IntSN' AND SNRuleName = 'ProductSNRule' AND OnPlantID=@OnPlant
                AND EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.LotName)
            
                INSERT INTO #FinalCO_SN
                SELECT a.LotName,a.SourceLotName,a.SNCust,b.MaterialID,c.ComMaterials,b.MESOrderID,b.OnPlantID,c.VendorID,c.DateCode,c.SNNote FROM #FinalLotName a 
                LEFT JOIN #WorkLotX5506 b ON a.LotName=b.SN
                LEFT JOIN #WorkSourceSNT16 c ON a.SourceLotName=c.SourceSN
            END
        END
    END
    
    /**
     * 3)条件判断结束
     **/
    IF EXISTS(SELECT 1 FROM #FinalLotName)
    BEGIN
        IF EXISTS(SELECT 1 FROM #FinalCO_SN)
        BEGIN--3.1
            SELECT a.matl_def_id,b.Descript,a.MESOrderID AS pom_order_id,a.SN AS LotName,a.SourceSN AS ComLot,
                   a.ComMaterials,c.Descript AS ComMatDes,a.VendorID,a.DateCode,a.SNNote,
                   OnPlantID,SNCust FROM #FinalCO_SN a
                   JOIN MMDefinitions b WITH(NOLOCK) ON a.matl_def_id=b.DefID
                   JOIN MMDefinitions c WITH(NOLOCK) ON a.ComMaterials=c.DefID
            WHERE NOT EXISTS(select distinct SN, SourceSN from #FinalCO_SN x 
                             where x.SN = a.SourceSN and x.SourceSN = a.SN)
        END
        ELSE
        BEGIN--3.2
            --3.2.1求解SN的必查字段
            SELECT SN,MaterialID,MESOrderID,OnPlantID INTO #FinalSNX1 FROM CO_SN_GENERATION a WITH(NOLOCK)
            WHERE SNType='IntSN' AND SNRuleName = 'ProductSNRule' AND OnPlantID=@OnPlant
            AND EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.LotName)
            --3.2.2求解SourceSN的必查字段
            SELECT a.SN AS SourceLotName,a.VendorID,a.DateCode,a.SNNote,a.MaterialID AS ComMaterials INTO #FinalSNX2 FROM CO_SN_GENERATION a WITH(NOLOCK) WHERE EXISTS(SELECT 1 FROM #FinalLotName b WHERE a.SN=b.SourceLotName)
            
            SELECT b.MaterialID AS matl_def_id,x.Descript,b.MESOrderID AS pom_order_id,b.SN AS LotName,c.SourceLotName AS ComLot,c.ComMaterials,y.Descript AS ComMatDes,c.VendorID,c.DateCode,c.SNNote,b.OnPlantID,a.SNCust
            FROM #FinalLotName a
            LEFT JOIN #FinalSNX1 b ON a.LotName=b.SN
            LEFT JOIN #FinalSNX2 c ON a.SourceLotName=c.SourceLotName
            JOIN MMDefinitions x WITH(NOLOCK) ON b.MaterialID=x.DefID
            JOIN MMDefinitions y WITH(NOLOCK) ON c.ComMaterials=y.DefID
            WHERE NOT EXISTS(
                SELECT DISTINCT * FROM #FinalLotName z
                WHERE z.LotName=a.SourceLotName and z.SourceLotName=a.LotName
            )
        END
    END
    ELSE
    BEGIN
        IF EXISTS(SELECT 1 FROM #FinalCO_SN)
        BEGIN--3.3
            SELECT a.matl_def_id,b.Descript,a.MESOrderID AS pom_order_id,a.SN AS LotName,a.SourceSN AS ComLot,
                   a.ComMaterials,c.Descript AS ComMatDes,a.VendorID,a.DateCode,a.SNNote,
                   OnPlantID,SNCust FROM #FinalCO_SN a
                   JOIN MMDefinitions b WITH(NOLOCK) ON a.matl_def_id=b.DefID
                   JOIN MMDefinitions c WITH(NOLOCK) ON a.ComMaterials=c.DefID
            WHERE NOT EXISTS(select distinct SN, SourceSN from #FinalCO_SN x 
                             where x.SN = a.SourceSN and x.SourceSN = a.SN)
        END
        ELSE
        BEGIN--3.4
            PRINT 'There is no queryable condition,please enter at less a query conditon.'
        END
    END
    
END
GO

虽然牺牲了代码的可读性，但创造了性能价值。本人水平有限，还请各位不吝赐教！

最后，将SSRS报表替换成此存储过程后，SQL查询分析器是秒查的。B/S前端用时1~2秒！

四. 总结

平常的你是否偶尔会因急于完成任务而书写一堆性能极低的SQL语句呢？写出可靠性能的SQL语句不难，难的是习惯。

本文的优化思想很简单，关键点是避免全表扫描 & 注重SQL语句写法 & 索引，另外，如果你查询的表有可能会在查询时段更新，而实际业务需求允许脏读，可加with(nolock)预防查询被更新事物阻塞。

希望本文对你有帮助。