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java - 不以逗号分隔的 Java JPA Left Join

问题描述

JPA结构中MYSQL结构翻译错误

我有 100% 的 mysql 查询：

SELECT DISTINCT * FROM list_orders LEFT JOIN orders_translate where list_orders._id=orders_translate._order_id

query JPA String query = "SELECT t1 FROM ListOrders t1 LEFT JOIN t1.speakers e WHERE e._id = t1._id";

public class OrdersTranslate implements Serializable {

private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "_id")
private Long id;
@Size(max = 50)
@Column(name = "_english_name")
private String englishName;
@Size(max = 50)
@Column(name = "_arabic_name")
private String arabicName;
@Size(max = 50)
@Column(name = "_russian_name")
private String russianName;
@Size(max = 50)
@Column(name = "_french_name")
private String frenchName;
@Basic(optional = false)
@NotNull
@Column(name = "_order_id")
private int order_id;

}

公共类 ListOrders 实现 Serializable {

private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "_id")
@SerializedName("_id")
private Integer id;
@Basic(optional = false)
@NotNull
@Column(name = "_number_id")
@SerializedName("_number_id")
private int numberId;
@Basic(optional = false)
@NotNull
@Size(min = 1, max = 50)
@Column(name = "name")
@SerializedName("name")
private String name;
@OneToOne(cascade = CascadeType.ALL)
private List<OrdersTranslate> speakers;

}

我得到下一个错误：

[53, 54] FROM 子句具有'ListOrders t1 LEFT JOINN t1.oerders'和'e'，它们没有用逗号分隔。[42, 53] 标识变量“t1.oerders”未遵循 Java 标识符的规则。[56, 56] 必须为范围变量声明提供标识变量。

JPA查询有什么问题？MySQL 查询工作正常！

标签： javamysqljpa

解决方案

起初 - 如果您在 ListOrders 表中有 OrdersTranslate 数组，则您没有 OneToOne 连接。这是 OneToMany 加入。

请在您的 ListOrders 课程中尝试：

@OneToMany(mappedBy="listOrders")
private List<OrdersTranslate> speakers;

在您的 OrdersTranslate 类中：

@ManyToOne
@JoinColumn(name = "_order_id")
private ListOrders listOrders;

然后您的 JPA 查询将如下所示：

SELECT t1 FROM ListOrders t1 LEFT JOIN t1.speakers e

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