实战：上亿数据如何秒查

心已赠人 2022-03-25 15:04 174阅读 0赞

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。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTIwNDUwNDU_size_16_color_FFFFFF_t_70][]

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。

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