DAO 如何映射 SQL 函数返回的字段？

Question

我正在为我的 API 使用 dropwizard 框架。我有一个命名查询如下：

@NamedQuery(name = "com.myapp.entity.MyEntity.findByMatchId", query = "SELECT test.name, count(test) as count FROM MyEntity as test,Entity1 as d where test.drug=d.id and test.drug.id= :drugId group by test.name") })

我正在返回 count(test) 函数的结果作为名称 count。下面是我的实体 class :

@NamedQuery(name = "com.myapp.entity.MyEntity.findByMatchId", query = "SELECT test.name, count(test) as count FROM MyEntity as test,Entity1 as d where test.drug=d.id and test.drug.id= :drugId group by test.name") })

@Entity
@Table(name = "my_entity")
@NamedQueries({
        @NamedQuery(name = "com.myapp.entity.MyEntity.findByMatchId", query = "SELECT test.name, count(test) as count FROM MyEntity as test,Entity1 as d where test.drug=d.id and test.drug.id= :drugId group by test.name") }))
public class MyEntity {

        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Long id;

        @Column(name = "name")
        private String name;

        @JsonBackReference("drug_id")
        @ManyToOne(fetch = FetchType.LAZY)
        @JoinColumn(name = "drug_id", nullable = false)
        private Drug drug;

        @Column(name = "timestamp", nullable = false)
        private Date timestamp;

        // This value is not getting mapped 
        private Long count;

        public Long getId() {
            return id;
        }

        public void setId(Long id) {
            this.id = id;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public Drug getDrug() {
            return drug;
        }

        public void setDrug(Drug drug) {
            this.drug = drug;
        }

        public Date getTimestamp() {
            return timestamp;
        }

        public void setTimestamp(Date timestamp) {
            this.timestamp = timestamp;
        }

        public SideEffectSeverity getSideEffectSeverity() {
            return sideEffectSeverity;
        }

        public void setSideEffectSeverity(SideEffectSeverity sideEffectSeverity) {
            this.sideEffectSeverity = sideEffectSeverity;
        }

        public Long getCount() {
            return count;
        }

        public void setCount(Long count) {
            this.count = count;
        }

    }

这里要怎么做才能正确映射count函数的值作为count。

为什么我的映射没有正确发生，我必须给它一些注释吗？

Answer 1

以上查询得到结果了吗？

如果是，请注意 return 类型的 count() 函数会很长。所以希望你已经尝试过用 DTO 映射响应（它应该包含两个字段作为名称和计数）。

Answer 2

您使用的是 OracleSQL 还是 POSTgreSQL？

Count 是一个保留字，重命名您的列将解决这个问题

   @Column(name = "count1")
   private Long count;

DAO 如何映射 SQL 函数返回的字段？

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