如何在Spring Boot Data Jpa应用程序中使用条件查询

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如何解决如何在Spring Boot Data Jpa应用程序中使用条件查询？

来自 docs

像这样定义一个接口

public interface studentRepositoryCustom {

    List<String> nameByCourse(String courseName);

}

然后像这样定义此接口的自定义实现

@service
class studentRepositoryImpl implements studentRepositoryCustom {

    @PersistenceContext
    private Entitymanager em;

    public List<String> nameByCourse(String courseName) {            
        CriteriaBuilder cb = em.getCriteriaBuilder();
        //Using criteria builder you can build your criteria querIEs.
    }

}

现在，您可以像这样在JPA存储库中扩展此自定义存储库实现。

public interface studentRepository extends CrudRepository<studentEntity, Integer>, studentRepositoryCustom {

}

了解有关条件查询和条件构建器的更多信息 here

解决方法

public interface studentRepository extends CrudRepository<studentEntity,Integer>{
    @Query(value = "" 
        + "SELECT s.studentname "
        + "FROM   studententity s,"
        + "       courseentity c "
        + "WHERE  s.coursEID = c.coursEID "
        + "       AND s.coursEID IN (SELECT c.coursEID "
        + "                          FROM   courseentity c "
        + "                          WHERE  c.coursename = ?1)")
    List<String> nameByCourse(String courseName);
}