如何将mysql查询转换为JPQL答案

【问题标题】：how to convert mysql query to JPQL如何将mysql查询转换为JPQL
【发布时间】：2021-02-09 16:50:19
【问题描述】：

如何将 MYSQL 查询转换为 JPQL 查询？是否可以使用相同的查询来更新 Java swing Program 中的实体而不是转换？

mysql查询select * from project.newproject; update newproject set pedate = date_add(psdate, interval duration day)

我的实体类如下所示

@Entity
@Table(name = "newproject")
@XmlRootElement

@Transient
 private PropertyChangeSupport changeSupport = new PropertyChangeSupport(this);

    private static final long serialVersionUID = 1L;
    @Id
    @Basic(optional = false)
    @Column(name = "pid")
    private Integer pid;
    @Basic(optional = false)
    @Column(name = "pname")
    private String pname;
    @Basic(optional = false)
    @Column(name = "psdate")
    @Temporal(TemporalType.DATE)
    private Date psdate;
    @Basic(optional = false)
    @Column(name = "duration")
    private int duration;
    @Column(name = "pedate")
    @Temporal(TemporalType.DATE)
    private Date pedate;

【问题讨论】：

标签： java mysql jpa

【解决方案1】：

我如下更改了 MYSQL 查询以更新所选行

`update newproject 
set pedate = date_add(psdate, interval duration day)
where pid = newproject.pid;`

并在 Java 中使用 createnativeQuery 更新选定的行

Newproject_1 p = ProjectPUEntityManager.find(Newproject_1.class, 1);

ProjectPUEntityManager.getTransaction().begin();
Query query = ProjectPUEntityManager.createNativeQuery("update newproject \n" +
"set pedate = date_add(psdate, interval duration day)\n" +
"where pid = newproject.pid;");
int count = query.executeUpdate();
ProjectPUEntityManager.merge(p);
ProjectPUEntityManager.getTransaction().commit();

JOptionPane.showMessageDialog(rootPane, "Update End Date");

【讨论】：