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，并且在购买表customer_coupons之后保存customers_id和{{ 1}}（客户可以有很多优惠券，而优惠券可以有很多顾客）。
我需要某种方式通过coupons_id表中的customerId和couponId获取客户的优惠券。我有界面customer_coupons：
CouponRepository但是这个查询不起作用，我得到@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);
}
。有人可以帮助我创建正确的查询吗？
答案 0 :(得分：0)
从客户中选择优惠券c加入c.coupons优惠券，其中c.id =：customerId和coupon.id =：couponId
JB Nizet的答案