我有两个表存储特定ReportingPeriod的LineItemTypes的Amounts和Adjustments。我正在寻找最有效的方法来查询两个表中存在的每个ReportingPeriod / LineItemType组合的金额和调整。
架构如下：
@ReportingPeriodComposition（1030行 - 表变量）
Src int,
GroupReportingPeriodId int,
ReportingPeriodId int,
ClientId int,
PeriodDate date,
...
PRIMARY KEY CLUSTERED (Src, ReportingPeriodId)
金额（约30,000,000行）
ReportingPeriodId int,
LineItemTypeId smallint,
Amount decimal,
PRIMARY KEY CLUSTERED (ReportingPeriodId, LineItemTypeId)
调整（约180,000行）
ReportingPeriodId int,
LineItemTypeId smallint,
Amount decimal,
Comment nvarchar(2500),
...
AdjustmentId int,
PRIMARY KEY NONCLUSTERED (AdjustmentId),
UNIQUE KEY CLUSTERED (ReportingPeriodId, LineItemTypeId)
我想通过唯一的ReportingPeriodId / LineItemTypeId选择Amounts和Adjustments，产生以下结果集：
| ReportingPeriodId | LineItemTypeId | Amount | Adjustment |
目前我正在使用以下查询，但我很想知道是否有人对如何更有效地完成此操作有所了解。欢迎所有建议！
SELECT
rpc.ReportingPeriodId,
COALESCE(a.LineItemTypeId, adj.LineItemTypeId) LineItemTypeId,
a.Amount,
adj.Amount Adjustment
FROM @ReportingPeriodComposition rpc
LEFT JOIN Watchlist.risk.Amount a
ON rpc.ReportingPeriodId = a.ReportingPeriodId
LEFT JOIN Watchlist.risk.Adjustment adj
ON rpc.ReportingPeriodId = adj.ReportingPeriodId
AND (a.ReportingPeriodId IS NULL OR a.LineItemTypeId = adj.LineItemTypeId)
WHERE
Src = @Src
AND (a.LineItemTypeId IS NOT NULL OR adj.LineItemTypeId IS NOT NULL)
请注意，@ Steve变量是确定我们需要从@ReportingPeriodComposition表变量中提取哪些源值所必需的。查询结果为~138,000行：
执行计划XML
<?xml version="1.0" encoding="utf-16"?>
<ShowPlanXML xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" Version="1.1" Build="10.0.4064.0" xmlns="http://schemas.microsoft.com/sqlserver/2004/07/showplan">
<BatchSequence>
<Batch>
<Statements>
<StmtSimple StatementCompId="9" StatementEstRows="104.769" StatementId="5" StatementOptmLevel="FULL" StatementOptmEarlyAbortReason="GoodEnoughPlanFound" StatementSubTreeCost="0.343989" StatementText="SELECT
 rpc.ReportingPeriodId,
 COALESCE(a.LineItemTypeId, adj.LineItemTypeId) LineItemTypeId,
 a.Amount,
 adj.Amount Adjustment
FROM @ReportingPeriodComposition rpc
LEFT JOIN Rating.risk.Amount a
 ON rpc.ReportingPeriodId = a.ReportingPeriodId
LEFT JOIN Rating.risk.Adjustment adj
 ON rpc.ReportingPeriodId = adj.ReportingPeriodId
 AND (a.ReportingPeriodId IS NULL OR a.LineItemTypeId = adj.LineItemTypeId)
WHERE
 Src = @Src
 AND (a.LineItemTypeId IS NOT NULL OR adj.LineItemTypeId IS NOT NULL)" StatementType="SELECT" QueryHash="0x425781A4C1D20919" QueryPlanHash="0xF3E9DD0ADAD04044">
<StatementSetOptions ANSI_NULLS="true" ANSI_PADDING="true" ANSI_WARNINGS="true" ARITHABORT="true" CONCAT_NULL_YIELDS_NULL="true" NUMERIC_ROUNDABORT="false" QUOTED_IDENTIFIER="true" />
<QueryPlan DegreeOfParallelism="1" CachedPlanSize="24" CompileTime="5" CompileCPU="5" CompileMemory="424">
<RelOp AvgRowSize="31" EstimateCPU="1.04769E-05" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimateRows="104.769" LogicalOp="Compute Scalar" NodeId="0" Parallel="false" PhysicalOp="Compute Scalar" EstimatedTotalSubtreeCost="0.343989">
<OutputList>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="ReportingPeriodId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="Amount" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="Amount" />
<ColumnReference Column="Expr1006" />
</OutputList>
<ComputeScalar>
<DefinedValues>
<DefinedValue>
<ColumnReference Column="Expr1006" />
<ScalarOperator ScalarString="CASE WHEN [Rating].[risk].[Amount].[LineItemTypeId] as [a].[LineItemTypeId] IS NOT NULL THEN [Rating].[risk].[Amount].[LineItemTypeId] as [a].[LineItemTypeId] ELSE [Rating].[risk].[Adjustment].[LineItemTypeId] as [adj].[LineItemTypeId] END">
<IF>
<Condition>
<ScalarOperator>
<Compare CompareOp="IS NOT">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="LineItemTypeId" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Const ConstValue="NULL" />
</ScalarOperator>
</Compare>
</ScalarOperator>
</Condition>
<Then>
<ScalarOperator>
<Identifier>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="LineItemTypeId" />
</Identifier>
</ScalarOperator>
</Then>
<Else>
<ScalarOperator>
<Identifier>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="LineItemTypeId" />
</Identifier>
</ScalarOperator>
</Else>
</IF>
</ScalarOperator>
</DefinedValue>
</DefinedValues>
<RelOp AvgRowSize="33" EstimateCPU="9.21971E-05" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimateRows="104.769" LogicalOp="Filter" NodeId="1" Parallel="false" PhysicalOp="Filter" EstimatedTotalSubtreeCost="0.343979">
<OutputList>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="ReportingPeriodId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="LineItemTypeId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="Amount" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="LineItemTypeId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="Amount" />
</OutputList>
<RunTimeInformation>
<RunTimeCountersPerThread Thread="0" ActualRows="137631" ActualEndOfScans="1" ActualExecutions="1" />
</RunTimeInformation>
<Filter StartupExpression="false">
<RelOp AvgRowSize="33" EstimateCPU="0.000437936" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimateRows="104.769" LogicalOp="Left Outer Join" NodeId="2" Parallel="false" PhysicalOp="Nested Loops" EstimatedTotalSubtreeCost="0.343886">
<OutputList>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="ReportingPeriodId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="LineItemTypeId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="Amount" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="LineItemTypeId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="Amount" />
</OutputList>
<RunTimeInformation>
<RunTimeCountersPerThread Thread="0" ActualRows="137647" ActualEndOfScans="1" ActualExecutions="1" />
</RunTimeInformation>
<NestedLoops Optimized="false" WithUnorderedPrefetch="true">
<OuterReferences>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="ReportingPeriodId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="ReportingPeriodId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="LineItemTypeId" />
<ColumnReference Column="Expr1009" />
</OuterReferences>
<RelOp AvgRowSize="26" EstimateCPU="0.000437936" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimateRows="104.769" LogicalOp="Left Outer Join" NodeId="4" Parallel="false" PhysicalOp="Nested Loops" EstimatedTotalSubtreeCost="0.00711828">
<OutputList>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="ReportingPeriodId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="ReportingPeriodId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="LineItemTypeId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="Amount" />
</OutputList>
<RunTimeInformation>
<RunTimeCountersPerThread Thread="0" ActualRows="137647" ActualEndOfScans="1" ActualExecutions="1" />
</RunTimeInformation>
<NestedLoops Optimized="false">
<OuterReferences>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="ReportingPeriodId" />
</OuterReferences>
<RelOp AvgRowSize="11" EstimateCPU="0.0001581" EstimateIO="0.003125" EstimateRebinds="0" EstimateRewinds="0" EstimateRows="1" LogicalOp="Clustered Index Seek" NodeId="5" Parallel="false" PhysicalOp="Clustered Index Seek" EstimatedTotalSubtreeCost="0.0032831" TableCardinality="0">
<OutputList>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="ReportingPeriodId" />
</OutputList>
<RunTimeInformation>
<RunTimeCountersPerThread Thread="0" ActualRows="1030" ActualEndOfScans="1" ActualExecutions="1" />
</RunTimeInformation>
<IndexScan Ordered="true" ScanDirection="FORWARD" ForcedIndex="false" ForceSeek="false" NoExpandHint="false">
<DefinedValues>
<DefinedValue>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="ReportingPeriodId" />
</DefinedValue>
</DefinedValues>
<Object Table="[@ReportingPeriodComposition]" Index="[PK__#6FDF7DF__F9ABEE3F71C7C670]" Alias="[rpc]" />
<SeekPredicates>
<SeekPredicateNew>
<SeekKeys>
<Prefix ScanType="EQ">
<RangeColumns>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="Src" />
</RangeColumns>
<RangeExpressions>
<ScalarOperator ScalarString="[@Src]">
<Identifier>
<ColumnReference Column="@Src" />
</Identifier>
</ScalarOperator>
</RangeExpressions>
</Prefix>
</SeekKeys>
</SeekPredicateNew>
</SeekPredicates>
</IndexScan>
</RelOp>
<RelOp AvgRowSize="22" EstimateCPU="0.000272246" EstimateIO="0.003125" EstimateRebinds="0" EstimateRewinds="0" EstimateRows="104.769" LogicalOp="Clustered Index Seek" NodeId="6" Parallel="false" PhysicalOp="Clustered Index Seek" EstimatedTotalSubtreeCost="0.00339725" TableCardinality="29974300">
<OutputList>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="ReportingPeriodId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="LineItemTypeId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="Amount" />
</OutputList>
<RunTimeInformation>
<RunTimeCountersPerThread Thread="0" ActualRows="137631" ActualEndOfScans="1030" ActualExecutions="1030" />
</RunTimeInformation>
<IndexScan Ordered="true" ScanDirection="FORWARD" ForcedIndex="false" ForceSeek="false" NoExpandHint="false">
<DefinedValues>
<DefinedValue>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="ReportingPeriodId" />
</DefinedValue>
<DefinedValue>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="LineItemTypeId" />
</DefinedValue>
<DefinedValue>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="Amount" />
</DefinedValue>
</DefinedValues>
<Object Database="[Rating]" Schema="[risk]" Table="[Amount]" Index="[PK_Amount]" Alias="[a]" IndexKind="Clustered" />
<SeekPredicates>
<SeekPredicateNew>
<SeekKeys>
<Prefix ScanType="EQ">
<RangeColumns>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="ReportingPeriodId" />
</RangeColumns>
<RangeExpressions>
<ScalarOperator ScalarString="@ReportingPeriodComposition.[ReportingPeriodId] as [rpc].[ReportingPeriodId]">
<Identifier>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="ReportingPeriodId" />
</Identifier>
</ScalarOperator>
</RangeExpressions>
</Prefix>
</SeekKeys>
</SeekPredicateNew>
</SeekPredicates>
</IndexScan>
</RelOp>
</NestedLoops>
</RelOp>
<RelOp AvgRowSize="18" EstimateCPU="0.000165111" EstimateIO="0.003125" EstimateRebinds="103.769" EstimateRewinds="0" EstimateRows="1" LogicalOp="Clustered Index Seek" NodeId="7" Parallel="false" PhysicalOp="Clustered Index Seek" EstimatedTotalSubtreeCost="0.33565" TableCardinality="178911">
<OutputList>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="LineItemTypeId" />
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="Amount" />
</OutputList>
<RunTimeInformation>
<RunTimeCountersPerThread Thread="0" ActualRows="1" ActualEndOfScans="137647" ActualExecutions="137647" />
</RunTimeInformation>
<IndexScan Ordered="true" ScanDirection="FORWARD" ForcedIndex="false" ForceSeek="false" NoExpandHint="false">
<DefinedValues>
<DefinedValue>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="LineItemTypeId" />
</DefinedValue>
<DefinedValue>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="Amount" />
</DefinedValue>
</DefinedValues>
<Object Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Index="[IX_Adjustment_ReportingPeriodId_LineItemTypeId]" Alias="[adj]" IndexKind="Clustered" />
<SeekPredicates>
<SeekPredicateNew>
<SeekKeys>
<Prefix ScanType="EQ">
<RangeColumns>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="ReportingPeriodId" />
</RangeColumns>
<RangeExpressions>
<ScalarOperator ScalarString="@ReportingPeriodComposition.[ReportingPeriodId] as [rpc].[ReportingPeriodId]">
<Identifier>
<ColumnReference Table="@ReportingPeriodComposition" Alias="[rpc]" Column="ReportingPeriodId" />
</Identifier>
</ScalarOperator>
</RangeExpressions>
</Prefix>
</SeekKeys>
</SeekPredicateNew>
</SeekPredicates>
<Predicate>
<ScalarOperator ScalarString="[Rating].[risk].[Amount].[ReportingPeriodId] as [a].[ReportingPeriodId] IS NULL OR [Rating].[risk].[Amount].[LineItemTypeId] as [a].[LineItemTypeId]=[Rating].[risk].[Adjustment].[LineItemTypeId] as [adj].[LineItemTypeId]">
<Logical Operation="OR">
<ScalarOperator>
<Compare CompareOp="IS">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="ReportingPeriodId" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Const ConstValue="NULL" />
</ScalarOperator>
</Compare>
</ScalarOperator>
<ScalarOperator>
<Compare CompareOp="EQ">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="LineItemTypeId" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Identifier>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="LineItemTypeId" />
</Identifier>
</ScalarOperator>
</Compare>
</ScalarOperator>
</Logical>
</ScalarOperator>
</Predicate>
</IndexScan>
</RelOp>
</NestedLoops>
</RelOp>
<Predicate>
<ScalarOperator ScalarString="[Rating].[risk].[Amount].[LineItemTypeId] as [a].[LineItemTypeId] IS NOT NULL OR [Rating].[risk].[Adjustment].[LineItemTypeId] as [adj].[LineItemTypeId] IS NOT NULL">
<Logical Operation="OR">
<ScalarOperator>
<Compare CompareOp="IS NOT">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Amount]" Alias="[a]" Column="LineItemTypeId" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Const ConstValue="NULL" />
</ScalarOperator>
</Compare>
</ScalarOperator>
<ScalarOperator>
<Compare CompareOp="IS NOT">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[Rating]" Schema="[risk]" Table="[Adjustment]" Alias="[adj]" Column="LineItemTypeId" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Const ConstValue="NULL" />
</ScalarOperator>
</Compare>
</ScalarOperator>
</Logical>
</ScalarOperator>
</Predicate>
</Filter>
</RelOp>
</ComputeScalar>
</RelOp>
<ParameterList>
<ColumnReference Column="@Src" ParameterRuntimeValue="(2)" />
</ParameterList>
</QueryPlan>
</StmtSimple>
</Statements>
</Batch>
</BatchSequence>
</ShowPlanXML>
答案 0 :(得分：2)
您发布的查询计划中没有任何特别糟糕的内容我可以看到 - 我怀疑SQL正在做出正确的选择。我唯一可以发现哪个稍微狡猾的是查询计划估计和返回的实际行数相差很远 - 这说明统计数据并不完全是最新的 - 您可以强制更新统计数据并查看是否继续使用相同的查询计划。
如果遇到性能不一致的问题，请在开发框上清除查询计划缓存并生成@SRC值的查询计划，该计划将产生非常少的行，然后清除计划缓存并生成查询计划一个@SRC值，该值将产生大量要返回的行。如果查询计划相同则可以，如果它们不同，则可能需要使用OPTIMIZE FOR提示。这有时会发生在参数化查询中，其中第一次运行它们会确定位于缓存中的计划 - 并且在该计划老化之前，后续运行的查询将使用相同的计划。
您现在必须通过审核来提供有关您遇到/希望解决的具体问题的更多信息？
答案 1 :(得分：1)
使用JOIN HINT怎么样？
来自MSDN：
LOOP |哈希| MERGE指定查询中的连接应该使用 循环，散列或合并。使用LOOP | HASH | MERGE JOIN强制执行 两个表之间的特定连接。 LOOP不能一起指定 使用RIGHT或FULL作为连接类型。
REMOTE指定在站点上执行连接操作 合适的桌子。当左表是本地表时，这很有用 右表是一个远程表。 REMOTE只应在使用时使用 左表的行数少于右表。
如果右表是本地的，则在本地执行连接。如果两者 表是远程的，但来自不同的数据源，REMOTE导致 加入要在右表的网站上执行。如果两个表 是来自同一数据源的远程表，不需要REMOTE。
当其中一个值被比较时，不能使用REMOTE 使用COLLATE将连接谓词强制转换为其他排序规则 子句。
REMOTE只能用于INNER JOIN操作。
在您的情况下，您可以使用LOOP加入，因为您正在处理LEFT加入。除了你的查询看起来很好，你在过滤的列上有索引吗？
您的金额表确实有很多行 - 但我已经看到了更多的数据库。你正在使用的硬件是什么？
有关如何使用LOOP JOIN并显示特定优化的示例，请参阅此article。但这一切都取决于使用连接提示时的查询类型。它可能不适用，在您的情况下应该是最后的选择。
答案 2 :(得分：0)
我会尝试用@table_variable表替换#temp，以便SQL Server可以使用更准确的统计信息。
目前，它假设表变量将返回1行并选择嵌套循环计划。如果它可以考虑实际的表基数，你可能会得到另一个。