Question

例如，我有一个包含3列的表A，其中包含相同的数据：

TABLE A
KEY  COL1  COL2  COL3
1    A     B     C
2    B     C     null
3    A     null  null
4    D     E     F
5    null  C     B
6    B     C     A
7    D     E     F

因此，我希望该表具有不同的值，并且顺序无关紧要。因此密钥1和6相同，密钥2和5以及密钥4和7也一样。

当然，我不能在选择项中使用仅过滤4和7的字符。

我可以使用非常复杂的case语句，也可以使用带order by的select中的select。但这需要在转换中使用，因此此处的性能是一个问题。有没有人能做到这一点？

我期望的结果

COL1  COL2  COL3
A     B     C
B     C     null
A     null  null
D     E     F

Answer 1

如果可以有很多列，则可以<?xml version="1.0" encoding="UTF-8" standalone="no"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>com.sac.arq.servicing.spring</groupId> <artifactId>pom-padre-frontend</artifactId> <version>5.4.4.4</version> </parent> <groupId>com.sac.ergo.riskbusinessadmissions</groupId> <artifactId>risk-business-admissions</artifactId> <packaging>jar</packaging> <version>1.0.0</version> <name>risk-business-admissions</name> <repositories /> <pluginRepositories /> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <podam.version>7.2.3.RELEASE</podam.version> <mockito-all.version>1.9.5</mockito-all.version> <mockito-core.version>1.9.5</mockito-core.version> <enax_bdd_test_core.version>1.1.7</enax_bdd_test_core.version> <enax_bdd_test_impl.version>1.1.5</enax_bdd_test_impl.version> <jackson-core.version>2.9.8</jackson-core.version> <jackson-annotations.version>2.9.8</jackson-annotations.version> <jacoco.version>0.8.3</jacoco.version> <eiaq_routines.version>1.0.6</eiaq_routines.version> <enax_validation.version>1.0.4</enax_validation.version> <conditions.version>1.0.2</conditions.version> <kygg_imcUtils.version>1.0.0</kygg_imcUtils.version> <openpojo.version>0.7.3</openpojo.version> <guava.version>27.1-jre</guava.version> <roo.version>2.0.0.RELEASE</roo.version>  </properties> <dependencies>  <dependency> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-servicing-core</artifactId> </dependency> <dependency> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-connector-rest</artifactId> </dependency> <dependency> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-restutils</artifactId> </dependency> <dependency> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-core-api</artifactId> </dependency> <dependency> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-backend-apx</artifactId> </dependency> <dependency> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-backend-commons</artifactId> </dependency> <dependency> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-backend-otma</artifactId> </dependency> <dependency> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-backend-ps</artifactId> </dependency> <dependency> <groupId>org.mapstruct</groupId> <artifactId>mapstruct</artifactId> <version>${org.mapstruct.version}</version> </dependency> <dependency> <groupId>org.hibernate.validator</groupId> <artifactId>hibernate-validator</artifactId> <version>6.0.9.Final</version> </dependency>       <dependency> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-servicing-logging</artifactId> </dependency>  <dependency> <groupId>com.sac.infrastructure.multichannel.api</groupId> <artifactId>multi-channel-infrastructure-api</artifactId> </dependency> <dependency> <groupId>com.sac.infrastructure.multichannel.serv</groupId> <artifactId>multi-channel-infrastructure-serv-facade</artifactId> </dependency>  <dependency> <groupId>org.springframework.roo</groupId> <artifactId>org.springframework.roo.annotations</artifactId> <scope>provided</scope> <type>pom</type> </dependency>  <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>${spring.version}</version> </dependency>  <dependency> <groupId>com.googlecode.openpojo</groupId> <artifactId>openpojo</artifactId> <version>${openpojo.version}</version> </dependency> <dependency> <groupId>commons-codec</groupId> <artifactId>commons-codec</artifactId> <version>${commons-codec.version}</version> </dependency>  <dependency> <groupId>com.wordnik</groupId> <artifactId>swagger-core_2.10</artifactId> <version>${swagger-core.version}</version> </dependency> <dependency> <groupId>com.wordnik</groupId> <artifactId>swagger-jaxrs_2.10</artifactId> <version>${swagger-jaxrs.version}</version> </dependency>  <dependency> <groupId>uk.co.jemos.podam</groupId> <artifactId>podam</artifactId> <version>${podam.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.mockito</groupId> <artifactId>mockito-all</artifactId> <version>${mockito-all.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>org.mockito</groupId> <artifactId>mockito-core</artifactId> <scope>test</scope> </dependency>  <dependency> <groupId>com.sac.enax.test</groupId> <artifactId>enax_bdd_test_core</artifactId> <version>${enax_bdd_test_core.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>com.sac.enax.global.bdd</groupId> <artifactId>enax_bdd_test_impl</artifactId> <version>${enax_bdd_test_impl.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-core</artifactId> <version>${jackson-core.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-annotations</artifactId> <version>${jackson-annotations.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>com.google.guava</groupId> <artifactId>guava</artifactId> <version>${guava.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>${httpclient.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpcore</artifactId> <version>${httpcore.version}</version> <scope>test</scope> </dependency>  <dependency> <groupId>com.sac.eiaq</groupId> <artifactId>eiaq_routines</artifactId> <exclusions> <exclusion> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-connector-host-api</artifactId> </exclusion> <exclusion> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-connector-host-apx</artifactId> </exclusion> </exclusions> <version>${eiaq_routines.version}</version> </dependency> <dependency> <groupId>com.sac.enax</groupId> <artifactId>enax_validation</artifactId> <exclusions> <exclusion> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-connector-host-api</artifactId> </exclusion> <exclusion> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-connector-host-apx</artifactId> </exclusion> </exclusions> <version>${enax_validation.version}</version> </dependency> <dependency> <groupId>com.sac.enax</groupId> <artifactId>conditions</artifactId> <exclusions> <exclusion> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-connector-host-api</artifactId> </exclusion> <exclusion> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-connector-host-apx</artifactId> </exclusion> </exclusions> <version>${conditions.version}</version> </dependency> <dependency> <groupId>com.sac.kygg</groupId> <artifactId>kygg_imcUtils</artifactId> <version>${kygg_imcUtils.version}</version> </dependency> </dependencies> <build> <finalName>ergo_${project.artifactId}</finalName>  <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <configuration> <source>${java.version}</source> <target>${java.version}</target> <annotationProcessorPaths> <path> <groupId>org.mapstruct</groupId> <artifactId>mapstruct-processor</artifactId> <version>${org.mapstruct.version}</version> </path> </annotationProcessorPaths> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>${arq.spring.jdk.version}</source> <target>${arq.spring.jdk.version}</target> <encoding>UTF-8</encoding> <useIncrementalCompilation>false</useIncrementalCompilation> <annotationProcessorPaths> <path> <groupId>org.mapstruct</groupId> <artifactId>mapstruct-processor</artifactId> <version>${org.mapstruct.version}</version> </path>  </annotationProcessorPaths> <compilerArgs> <arg>-proc:only</arg> </compilerArgs> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-resources-plugin</artifactId> <version>${maven-resources-plugin.version}</version> <configuration> <encoding>UTF-8</encoding> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-assembly-plugin</artifactId> <configuration> <descriptors> <descriptor>generacionFacade.xml</descriptor> <descriptor>generacionSN.xml</descriptor> </descriptors> <outputDirectory>target</outputDirectory> </configuration> <executions> <execution> <id>make-assembly</id> <phase>package</phase> <goals> <goal>single</goal> </goals> </execution> </executions> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-deploy-plugin</artifactId> <version>${maven-deploy-plugin.version}</version> </plugin> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>aspectj-maven-plugin</artifactId> <version>${aspectj-maven-plugin.version}</version> <configuration> <complianceLevel>${arq.spring.jdk.version}</complianceLevel> <outxml>true</outxml> <aspectLibraries> <aspectLibrary> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> </aspectLibrary> <aspectLibrary> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-servicing-core</artifactId> </aspectLibrary> <aspectLibrary> <groupId>com.sac.jee.arq.spring.core</groupId> <artifactId>arq-spring-restutils</artifactId> </aspectLibrary> </aspectLibraries> <source>${arq.spring.jdk.version}</source> <target>${arq.spring.jdk.version}</target> </configuration> <executions> <execution> <phase>process-sources</phase> <goals> <goal>compile</goal> <goal>test-compile</goal> </goals> </execution> </executions> <dependencies> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjrt</artifactId> <version>${aspectj.version}</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjtools</artifactId> <version>${aspectj.version}</version> </dependency> </dependencies> </plugin>  <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-surefire-plugin</artifactId> <version>${maven-surefire-plugin.version}</version> <configuration> <argLine>${surefireArgLine} -XX:-UseSplitVerifier</argLine> <printSummary>false</printSummary> <redirectTestOutputToFile>true</redirectTestOutputToFile> <excludes> <exclude>**/*_Roo_*</exclude> <exclude>${skip.tests}</exclude> </excludes> </configuration> </plugin> <plugin> <groupId>org.jacoco</groupId> <artifactId>jacoco-maven-plugin</artifactId> <version>${jacoco.version}</version> <configuration> <excludes> <exclude>com/sac/enax/cards/dao/model/**/*.class</exclude> </excludes> </configuration> <executions> <execution> <id>pre-unit-test</id> <goals> <goal>prepare-agent</goal> </goals> <configuration> <destFile>${project.build.directory}/jacoco.exec</destFile> <propertyName>surefireArgLine</propertyName> </configuration> </execution> <execution> <id>post-unit-test</id> <phase>test</phase> <goals> <goal>report</goal> </goals> <configuration> <dataFile>${project.build.directory}/jacoco.exec</dataFile> <outputDirectory>${project.reporting.outputDirectory}/jacoco</outputDirectory> </configuration> </execution> </executions> </plugin>  <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-eclipse-plugin</artifactId> <version>${maven-eclipse-plugin.version}</version>  <configuration> <downloadSources>true</downloadSources> <downloadJavadocs>false</downloadJavadocs> <wtpversion>2.0</wtpversion> <additionalBuildcommands> <buildCommand> <name>org.eclipse.ajdt.core.ajbuilder</name> <arguments> <aspectPath>org.springframework.aspects</aspectPath> </arguments> </buildCommand> <buildCommand> <name>org.springframework.ide.eclipse.core.springbuilder</name> </buildCommand> </additionalBuildcommands> <additionalProjectnatures> <projectnature>org.eclipse.ajdt.ui.ajnature</projectnature> <projectnature>com.springsource.sts.roo.core.nature</projectnature> <projectnature>org.springframework.ide.eclipse.core.springnature</projectnature> </additionalProjectnatures> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-idea-plugin</artifactId> <version>${maven-idea-plugin.version}</version> <configuration> <downloadSources>true</downloadSources> <dependenciesAsLibraries>true</dependenciesAsLibraries> </configuration> </plugin>  <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>tomcat-maven-plugin</artifactId> <version>${tomcat-maven-plugin.version}</version> </plugin> <plugin> <groupId>org.mortbay.jetty</groupId> <artifactId>jetty-maven-plugin</artifactId> <version>${jetty-maven-plugin.version}</version> <configuration> <webAppConfig> <contextPath>/${project.name}</contextPath> </webAppConfig> </configuration> </plugin> </plugins> </build> <profiles> <profile> <id>unit-test</id> <activation> <activeByDefault>true</activeByDefault> </activation> <properties> <build.profile.id>unit-test</build.profile.id> <skip.tests>**/RunIntegradoTest.java</skip.tests> </properties> </profile> <profile> <id>integration-test</id> <properties> <build.profile.id>integration-test</build.profile.id> <skip.tests>**/business/**, **/dao/**, **/facade/**, **/TestGetterSetter.java</skip.tests> </properties> </profile> </profiles> </project>然后对值进行排序，然后依次UNPIVOT并进行PIVOT行：

Oracle设置：

DISTINCT

查询：

CREATE TABLE table_name ( KEY, COL1, COL2, COL3 ) AS
SELECT 1,    'A',     'B',     'C'  FROM DUAL UNION ALL
SELECT 2,    'B',     'C',     null FROM DUAL UNION ALL
SELECT 3,    'A',     null,    null FROM DUAL UNION ALL
SELECT 4,    'D',     'E',     'F'  FROM DUAL UNION ALL
SELECT 5,    null,    'C',     'B'  FROM DUAL UNION ALL
SELECT 6,    'B',     'C',     'A'  FROM DUAL UNION ALL
SELECT 7,    'D',     'E',     'F'  FROM DUAL

输出：

COL1 | COL2 | COL3
:--- | :--- | :---
A    | B    | C   
B    | C    | null
D    | E    | F   
A    | null | null

db <>提琴here

Answer 2

复杂的case表达式将具有最佳性能。但是最简单的方法是条件聚合：

select key,
       max(case when seqnum = 1 then col end) as col1,
       max(case when seqnum = 2 then col end) as col2,
       max(case when seqnum = 3 then col end) as col3
from (select key,col,
             row_number() over (partition by key order by col asc) as seqnum
      from ((select key, col1 as col from t) union all
            (select key, col2 as col from t) union all
            (select key, col3 as col from t)
           ) kc
      where col is not null
     ) kc
group by key;

按其值对列进行排序

2 个答案: