Spring Boot JPA查询的关键字为空和空

Question

我使用的是spring boot版本2.0.3.Release和spring data jpa版本2.0.8.Release。我有两个表TableA、TableB，它们是一对一映射的。

@Entity
@Table(name = "table_a")
public class TableA {

     @Id
     @Column(name = "id")
     private Long id;

     @OneToOne(mappedBy = "table_b", cascade = CascadeType.ALL)
     private TableB tableB;
}

@Entity
@Table(name = "table_b")
public class TableB {

     @Id
     @Column(name = "id")
     private Long id;

     @OneToOne
     @JoinColumn(name = "id")
     private TableA tableA;
}

@Query(value = "select a from TableA a where a.tableB is null and a.id=?1")
TableA findTableAValues(Long id);

Answer 1

IS EMPTY运算符是IS NULL的逻辑等价物，但用于集合。

您可以访问此链接获得更多详细信息和示例http://www.java2s.com/tutorials/java/jpa/4070__jpa_query_is_empty.htm