MySQL到JPA/JPQL查询

Question

我试图将我的Mysql查询转换为JPQL，但我不知道哪个工具可以在eclipse上使用而无需编译。

我的日志没有告诉我哪里是错误，所以我找不到哪里是错误的语法。

@Entity
@Table(name="computer")
//@NamedQuery(name="computer.rowsWithFilter", query="select count(c.id) from computer c left join company comp on c.company_id = comp.id where c.name like :filter") 
public class Computer {

    @Id @GeneratedValue
    private long id;

    @Column(name="name")
    private String name;

    @Column(name="introduced")
    private LocalDate introduced;

    @Column(name="discontinued")
    private LocalDate discontinued;

    @ManyToOne
    private Company company;

public class Company {

    @Id
    @GeneratedValue
    private long id;

    @Column(name="name")
    private String name;

谢谢你的帮助！

Answer 1

试试这个：

SELECT COUNT(c.id) 
FROM computer c 
LEFT JOIN c.company comp
where c.name like :filter