CrudRepository: Return one result, ordered by a column
java, jpa, mysql, spring-data
Solution
Bludream's answer from setMaxResults for Spring-Data-JPA annotation?… has the answer.
The syntax is "findFirst" or "findTop10" though it still returns a list.
List<ImportReceipt> findFirstByImportTypeOrderByTimestampDesc(String importType);
I suppose List will always be of size() 0 or 1.
Problem
Is there a way for a CrudRepository interface to sort a table with multiple rows and simply return the first row, e.g. sort by a timestamp to return only the latest row? ``` public interface ImportReceiptRepository extends CrudRepository<ImportReceipt, Long> { ImportReceipt getOneByImportTypeOrderByTimestampDesc(String importType); ImportReceipt findOneByImportTypeOrderByTimestampDesc(String importType); } ``` Both findOneBy... and getOneBy... throw: ``` org.springframework.dao.IncorrectResultSizeDataAccessException: result returns more than one elements; nested exception is javax.persistence.NonUniqueResultException: result returns more than one elements at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:395) at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:216) at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:417) at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:59) at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213) at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:147) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.data.jpa.repository.support.LockModeRepositoryPostProcessor$LockModePopulatingMethodIntercceptor.invoke(LockModeRepositoryPostProcessor.java:105) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207) at com.sun.proxy.$Proxy109.findOneByImportTypeOrderByTimestampDesc(Unknown Source) at edu.ucdavis.dss.dw.services.DefaultImportReceiptService.getLatestOneByImportType(DefaultImportReceiptService.java:26) ... ``` Or, putting it another way, what's the CrudRepository equivalent of: ``` SELECT * FROM ImportReceipts ORDER BY timestamp DESC LIMIT 0,1; ```