Question

我正在使用java.lang.IllegalStateException: Failed to load ApplicationContext at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124) at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83) at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:189) at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:131) at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:230) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:228) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:287) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:289) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:247) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191) at org.junit.runner.JUnitCore.run(JUnitCore.java:137) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:119) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:42) at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234) at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144) Caused by: java.lang.NullPointerException at org.springframework.test.context.web.socket.MockServerContainerContextCustomizer.customizeContext(MockServerContainerContextCustomizer.java:38) at org.springframework.boot.test.context.SpringBootContextLoader$ContextCustomizerAdapter.initialize(SpringBootContextLoader.java:270) at org.springframework.boot.SpringApplication.applyInitializers(SpringApplication.java:633) at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:347) at org.springframework.boot.SpringApplication.run(SpringApplication.java:311) at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:111) at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98) at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116) ... 29 more运算符，并且返回了不需要的数据类型。查询返回univoted数据的nvarchar数据类型。当连接到具有varchar数据类型的表时，我得到一个隐式类型转换。以下是将产生这些结果的示例。

有没有办法控制UNPIVOT返回的输出数据类型？我希望UNPIVOT返回varchar数据类型。

UNPIVOT

Answer 1

UNPIVOT函数有点奇怪，因为它将从各个列（具有相同的数据类型和长度）获取数据并将其转换为行。

虽然它转换了数据，但它似乎确实做了一些假设。例如，您的Volume列获取int的数据类型，因为这是您未分配的每个列的数据类型，但问题出在您的VolumeType列上 - 引擎不知道是否您有一个varchar或nvarchar数据，因此当您执行unpivot时，它会提供nvarchar(256)。

如果您不想进行隐式类型转换，那么我建议您使用CROSS APPLY取消隐藏数据。它还有一些代码行，但如果需要，您可以包含显式数据类型。这是一个例子：

select *
from
(
    select Facility, Dt, VolumeType, Volume
    from #Data
    cross apply
    (
        select 'VolumeType1', VolumeType1 union all
        select 'VolumeType2', VolumeType2 union all
        select 'VolumeType3', VolumeType3
    ) c (VolumeType, Volume)
) UNP
JOIN #Map
        ON UNP.Facility = #Map.Facility
            AND UNP.VolumeType = #Map.VolumeType;

See Demo。这应该删除隐式转换，但如果它没有，那么您可以在CROSS APPLY内执行转换：

select *
from
(
    select Facility, Dt, VolumeType, Volume
    from #Data
    cross apply
    (
        select cast('VolumeType1' as varchar(15)), VolumeType1 union all
        select cast('VolumeType2' as varchar(15)), VolumeType2 union all
        select cast('VolumeType3' as varchar(15)), VolumeType3
    ) c (VolumeType, Volume)
) UNP
JOIN #Map
        ON UNP.Facility = #Map.Facility
            AND UNP.VolumeType = #Map.VolumeType;

See Demo。

您的问题非常类似于我在DBA.SE上发布的问题，关于UNPIVOT要求所有数据类型长度相同的原因。

UNPIVOT返回数据类型

1 个答案: