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SELECT COUNT(*) FROM people 使用JpaRepository 分配结果:to Integer count？

Answer 1

@Formula帮助您创建自己的公式Hibernate.

@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;