Spring Data Hibernate JPQL 聚合查询

Question

我有一个带有实体的 Spring Data 实现

@Entity
public class Account extends AbstractEntity {

...

    @OneToMany(mappedBy = "account")
    private Set<AccountTransaction> accountTransactions;

还有AccountTransactions

@Entity(name="AccountTransactions")
public class AccountTransaction extends AbstractEntity {

    /**
     * 
     */
    private static final long serialVersionUID = -7045838402463741959L;

    @ManyToOne(optional = false)
    @JsonIgnore
    private Account account;

    @Column
    @Enumerated(EnumType.ORDINAL)
    private TransactionType transactionType;

    @Column
    private BigDecimal amount;

还有我正在尝试执行聚合查询的存储库：sum(amount)

然而结果是null

public interface AccountTransactionRepository extends
        CrudRepository<AccountTransaction, Long> {

    // @Query(value =
    // "select sum(amount) from AccountTransaction where account.id = ?1")
    @Query(value = "SELECT sum(at.amount) FROM AccountTransactions at WHERE at.account.id = :accountId")
    public BigDecimal getAccountBalance(@Param("accountId") Long accountId);
}

我需要做什么才能得到amount 列的BigDecimal 总和？

*更新*

我能够让查询工作，将其更改为 nativeQuery，如下所示：

@Query(value = "SELECT sum(amount) FROM account_transaction WHERE account_id = :accountId", nativeQuery = true)
    public BigDecimal getAccountBalance(@Param("accountId") Long accountId);

这显然不太理想……因为我不想为每个查询都写这个……

Answer 1

您必须添加JoinColumn 才能建立关系：

@ManyToOne(optional = false)
@JoinColumn(name="FOREIGN_KEY_HERE")
@JsonIgnore
private Account account;