我正在尝试按子选择结果进行分组，以减少处理的数据量。
My_table有超过2000万行。
示例：
SELECT TOP 100 A.Column FROM (
SELECT TOP 500 Column FROM My_table) A
GROUP BY A.Column
我希望查询只能在我的表中使用500行，但是当我使用group by时，需要花费很多时间，比如当我只分组500时，它会将整个2000行分组。
有没有办法让sql motor只能用500行？
答案 0 :(得分：0)
如果与您无关，使用了哪500行，您是否考虑过使用<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
<Product Id="*" Name="DummyInstaller" Language="1033" Version="1.0.0.0" Manufacturer="Bryan" UpgradeCode="94D1BC64-7CC1-45DA-BD5F-8ED40980E75C">
<Package InstallerVersion="200" Compressed="yes" InstallScope="perMachine" Platform="x64"/>
<Property Id="JAVA_CURRENT_VERSION64">
<RegistrySearch Id="JRE_CURRENT_VERSION_REGSEARCH64" Root="HKLM" Key="SOFTWARE\JavaSoft\Java Runtime Environment" Name="CurrentVersion" Type="raw" Win64="yes" />
</Property>
<MajorUpgrade DowngradeErrorMessage="A newer version of [ProductName] is already installed." />
<MediaTemplate />
<Feature Id="ProductFeature" Title="DummyInstaller" Level="1" >
<!--<ComponentGroupRef Id="NewFilesGroup" />-->
<ComponentRef Id="REGISTRY_A" />
<ComponentRef Id="PROCRUN.EXE"/>
</Feature>
</Product>
<Fragment>
<Directory Id="TARGETDIR" Name="SourceDir">
<Directory Id="ProgramFiles">
<Directory Id="DummyDir" Name="DummyInstaller">
<!--<Directory Id="MyProgramDir" Name="MosquittoNew" />-->
<Directory Id="SERVERDIR" Name="Kube2UpdaterService">
<Component Id="REGISTRY_A" DiskId="1" Guid="*" Win64="no">
<RegistryKey Root="HKLM" Key="SOFTWARE\Apache Software Foundation\Procrun 2.0\Kube2UpdaterService\Parameters\Java" Action="createAndRemoveOnUninstall">
<RegistryValue Type="string" Name="Classpath" Value="E:\Service\Update_Service-1.0.jar" KeyPath="yes" />
<RegistryValue Type="string" Name="Jvm" Value="C:\Program Files\Java\jdk1.8.0_25\jre\bin\server\jvm.dll" />
<RegistryValue Type="multiString" Action="append" Name="Options">
<MultiStringValue Type="multiString" Name="Options" Action="append">-Duser.language=en</MultiStringValue>
<MultiStringValue Type="multiString" Name="Options" Action="append">-Duser.region=US</MultiStringValue>
</RegistryValue>
<RegistryValue Type="integer" Name="JvmMs" Value="256" />
<RegistryValue Type="integer" Name="JvmMx" Value="1024" />
<RegistryValue Type="integer" Name="JvmSs" Value="4000" />
</RegistryKey>
<RegistryKey Root="HKLM" Key="SOFTWARE\Apache Software Foundation\Procrun 2.0\Kube2UpdaterService\Parameters\Log" Action="createAndRemoveOnUninstall">
<RegistryValue Type="string" Name="Path" Value="c:\logs" />
<RegistryValue Type="string" Name="Level" Value="Error" />
<RegistryValue Type="string" Name="Prefix" Value="Kube2UpdaterService" />
<RegistryValue Type="string" Name="StdError" Value="c:\logs\stderr.txt" />
<RegistryValue Type="string" Name="StdOutput" Value="c:\logs\stdout.txt" />
</RegistryKey>
<RegistryKey Root="HKLM" Key="SOFTWARE\Apache Software Foundation\Procrun 2.0\Kube2UpdaterService\Parameters\Start" Action="createAndRemoveOnUninstall">
<RegistryValue Type="string" Name="Mode" Value="jvm" />
<RegistryValue Type="string" Name="Class" Value="com.kohls.kube.services.updater.UpdaterServiceMain" />
<RegistryValue Type="string" Name="Params" Value="start" />
</RegistryKey>
<RegistryKey Root="HKLM" Key="SOFTWARE\Apache Software Foundation\Procrun 2.0\Kube2UpdaterService\Parameters\Stop" Action="createAndRemoveOnUninstall">
<RegistryValue Type="string" Name="Mode" Value="jvm" />
<RegistryValue Type="string" Name="Class" Value="com.kohls.kube.services.updater.UpdaterServiceMain" />
<RegistryValue Type="string" Name="Method" Value="stop" />
<RegistryValue Type="string" Name="Params" Value="stop" />
<RegistryValue Type="string" Name="StdOutput" Value="auto" />
</RegistryKey>
<RegistryKey Root="HKLM" Key="SYSTEM\CurrentControlSet\Services\Kube2UpdaterService" Action="createAndRemoveOnUninstall">
<RegistryValue Type="string" Name="Description" Value="Kube updater service performing updates and installation" />
<RegistryValue Type="string" Name="DisplayName" Value="Kube2UpdaterService" />
<RegistryValue Type="string" Name="ImagePath" Value="E:\Service\prunsrv.exe //RS//Kube2UpdaterService" />
<RegistryValue Type="string" Name="DependsOnService" Value="Tcpip Afd" />
<RegistryValue Type="string" Name="ObjectName" Value="LocalSystem" />
<RegistryValue Type="integer" Name="ErrorControl" Value="1" />
<RegistryValue Type="integer" Name="Start" Value="2" />
<RegistryValue Type="integer" Name="Type" Value="16" />
</RegistryKey>
<RegistryKey Root="HKLM" Key="SYSTEM\CurrentControlSet\Services\Kube2UpdaterService\Parameters" Action="createAndRemoveOnUninstall">
<RegistryValue Type="string" Name="Test" Value="Pass" />
</RegistryKey>
</Component>
<Component Id="PROCRUN.EXE" DiskId="1" Guid="468C2DB3-F722-4DE6-8A91-B6FB8009757D" Win64="no">
<!-- this is the renamed procrun 64 bit executable -->
<File Id="prunsrv.exe" Name="prunsrv.exe" Source="E:\Service\prunsrv.exe" />
<ServiceInstall Id="PROCRUN" Type="ownProcess" Name="Kube2UpdaterService" DisplayName="Kube2UpdaterService" Description="Kube 2.0 Updater Service" Start="auto" Account="LocalService" ErrorControl="normal" Arguments=" //RS//Kube2UpdaterService" />
<ServiceControl Id="StartPRUNSRV" Start="install" Stop="both" Remove="uninstall" Name="Kube2UpdaterService" Wait="no" />
</Component>
</Directory>
</Directory>
</Directory>
</Directory>
</Fragment>
</Wix>
？
set {rowcount number，textsize number} - 使SAP ASE服务器在指定的行数受到影响后停止处理查询（选择，插入，更新或删除）。数字可以是没有小数点的数字文字，也可以是整数类型的局部变量。