使用自定义查询（子查询）来休眠额外列

Question

@Entity
@Table(name="student")
public class Student
    @Id
    private Integer id;
    private String name;
    private Integer count;

我想分配给

  

计数

count = SELECT COUNT(*) FROM people

如何使用JpaRepository将结果：SELECT COUNT(*) FROM people分配给整数计数？

Answer 1

@Formula可帮助您在Hibernate中为自己的公式创建。

@Entity
@Table(name="student")
public class Student
    @Id
    private Integer id;
    private String name;
    @Formula("(SELECT COUNT(*) FROM people)")  // people is table name not entity
    private Integer count;