如何从具有ManyToMany关系的join表中获取对象？Spring + Hibernate

Question

我有两个实体：

@Entity
public class Customer {
@Id
@GeneratedValue
private int id;
@Column(nullable = false)
private String name;
@ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private Collection<Coupon> coupons;
}

@Entity
public class Coupon {
@Id
@GeneratedValue
private int id;
@Column(nullable = false)
private String title;
@ManyToMany(mappedBy = "coupons")
private Collection<Customer> customers;
}

数据库中有三个表：customer，coupon和customer_coupons，客户可以购买优惠券，在购买优惠券后，customer_coupons保存customers_id和coupons_id (客户可以有多个优惠券，优惠券可以有多个客户)。

我需要以某种方式从customer_coupons表中获得customerId和couponId客户的优惠券。我有CouponRepository接口：

@Repository
public interface CouponRepository extends JpaRepository<Coupon, Integer> {
    @Query("SELECT c FROM Coupon c WHERE c.id IN (SELECT coupons.id FROM customer_coupons WHERE coupons_id = ?1 AND customer_id = ?2)")
    Coupon findCustomerCoupon(int couponId, int customerId);
}

但是这个查询不起作用，我得到的是QuerySyntaxException: customer_coupons is not mapped。有人能帮我创建正确的查询吗？

Answer 1

从Customer c加入c.coupons优惠券中选择优惠券，其中c.id = :customerId和coupon.id =：优惠券AND

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