title: Why am I getting a NonUniqueResultException from my Spring Repository?
body: <p>I'm currently working on a web app that will rate neighbourhoods on a number of different criteria, one of which being statistics from the local Garda station (police station in Irish). I'm passing a latitude and longitude value from the client side into a controller in Spring and I want to run the following Haversine Formula in an SQL query so I can find the nearest police station and return the relevant statistics. (There are 41 stations in the database and the entities have a name, latitude and longitude variable).</p>
  
  <p>I'm getting the following error:</p>
  
  <pre><code>javax.persistence.NonUniqueResultException: result returns more than one elements
  </code></pre>
  
  <p>In my controller class, I'm getting a longitude and latitude value from the client side and storing them into a latitude and longitude variable with the following snippet. (As previously stated I find the nearest police station and return the relevant statistics but for now, I'm attempting to print the closest station's name in the console to ensure the method is working correctly before moving on)</p>
  
  <pre><code>@RequestMapping(value = "/results", method = RequestMethod.POST)
   @ResponseBody
   public String Submit(@Valid GardaStation gardaStation, @RequestParam("latitude") Double latitude,@RequestParam("longitude") Double longitude) {
  
      // Attempt at passing the lat and long input by user from the client side to the repository and returning the single top (or nearest) result
      gardaStation = gardaStationRepository.findTopByGardaStation_LatitudeAndGardaStation_Longitude(latitude, longitude);
      System.out.println(gardaStation.getGardaStation_name());
      return "/";
  }
  </code></pre>
  
  <p>In my GardaStationRepository, I'm running the following code which will query the database for the closest result based on the haversine formula. I added "top" to "findTopByGardaStation_LatitudeAndGardaStation_Longitude" repository function as I cannot use SQL's "LIMIT 1" to return a single row. [Using top instead of LIMIT] (<a href="https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#repositories.limit-query-result" rel="nofollow noreferrer">https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#repositories.limit-query-result</a>)!</p>
  
  <pre><code>static final String HAVERSINE_PART = "(6371 * acos(cos(radians(:latitude)) * cos(radians(m.gardaStation_latitude)) * cos(radians(m.gardaStation_longitude) - radians(:longitude)) + sin(radians(:latitude)) * sin(radians(m.gardaStation_latitude))))";
  
  @Query("SELECT m FROM GardaStation m ORDER BY "+HAVERSINE_PART+" DESC")
  public GardaStation findTopByGardaStation_LatitudeAndGardaStation_Longitude(@Param("latitude") final double latitude, @Param("longitude") final double longitude);
  </code></pre>
  
  <p>As I'm trying to pass a single GardaStation object in both the controller, repository, as well as using "top" in the repository function name why am I still getting the "result returns more than one elements" error?</p>
  
  <p>Full Error in console</p>
  
  <pre><code>javax.persistence.NonUniqueResultException: result returns more than one elements
      at org.hibernate.jpa.internal.QueryImpl.getSingleResult(QueryImpl.java:539) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final]
      at org.springframework.data.jpa.repository.query.JpaQueryExecution$SingleEntityExecution.doExecute(JpaQueryExecution.java:208) ~[spring-data-jpa-1.11.9.RELEASE.jar:na]
      at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:87) ~[spring-data-jpa-1.11.9.RELEASE.jar:na]
      at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:116) ~[spring-data-jpa-1.11.9.RELEASE.jar:na]
      at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:106) ~[spring-data-jpa-1.11.9.RELEASE.jar:na]
      at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:499) ~[spring-data-commons-1.13.9.RELEASE.jar:na]
      at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:477) ~[spring-data-commons-1.13.9.RELEASE.jar:na]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:56) ~[spring-data-commons-1.13.9.RELEASE.jar:na]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99) ~[spring-tx-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282) ~[spring-tx-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) ~[spring-tx-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136) ~[spring-tx-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133) ~[spring-data-jpa-1.11.9.RELEASE.jar:na]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57) ~[spring-data-commons-1.13.9.RELEASE.jar:na]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) ~[spring-aop-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at com.sun.proxy.$Proxy554.findTopByGardaStation_LatitudeAndGardaStation_Longitude(Unknown Source) ~[na:na]
      at com.charlie.FinalYearProject.controller.MappingController.Submit(MappingController.java:86) ~[classes/:na]
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_111]
      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_111]
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_111]
      at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_111]
      at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.13.RELEASE.jar:4.3.13.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [na:1.8.0_111]
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [na:1.8.0_111]
      at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.23.jar:8.5.23]
      at java.lang.Thread.run(Unknown Source) [na:1.8.0_111]
  </code></pre>