Question

我有一个名为Vote的课程：

@Table(name = "PHY_VOTE")
public class VoteEntity extends BaseEntity<Long> implements Comparable {

    public static final String TITLE = "title";
    public static final String VALUE = "value";
    public static final String USER = "user";

    private String title;
    private String value;

    private UserEntity user;

    public VoteEntity() {}

    public VoteEntity(Long id) {
        setId(id);
    }

    public VoteEntity(String title, String value, UserEntity user) {
        this.title = title;
        this.value = value;
        this.user = user;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    @Column(name = "VOTE_ID")
    @Override
    public Long getId() {
        return super.getId();
    }

    @FilterProperty(operation = FilterProperty.ILIKE)
    @Column(name = "TITLE", nullable = false, length = 100)
    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    @FilterProperty(operation = FilterProperty.ILIKE)
    @Column(name = "VALUE", nullable = false, length = 4)
    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    @ManyToOne
    @JoinColumn(name = "USER_ID", foreignKey = @ForeignKey(name = "PYH_VOTE_USER_FK"))
    public UserEntity getUser() {
        return user;
    }

    public void setUser(UserEntity user) {
        this.user = user;
    }

    @Transient
    @Override
    public String getOptionsTitleProperty() {
        return TITLE;
    }

}

如何使用Criteria创建以下命令？

从PHY_VOTE t GROUP BY t.TITLE中选择t.TITLE，ROUND（SUM（t.VALUE）/ COUNT（t.TITLE），2）值

Answer 1

您可以考虑使用FluentJPA来做到这一点：

public AverageByTitle getAverageByTitle() {
    FluentQuery query = FluentJPA.SQL((VoteEntity t) -> {

        Alias<Number> avg = alias(ROUND(SUM(INT.raw(t.getValue())) / COUNT(t.getTitle()), 2),
                AverageByTitle::getAverage);

        SELECT(t.getTitle(), avg);
        FROM(t);
        GROUP(BY(t.getTitle()));
    });

    return query.createQuery(em, AverageByTitle.class).getSingleResult();
}

// declarations

public static final DataType<Integer> INT = DataTypes.INT;

@Tuple
@Data // lombok
public static class AverageByTitle {
    private String title;
    private float average;
}

产生以下SQL：

SELECT t0.TITLE, ROUND((SUM(t0.VALUE) / COUNT(t0.TITLE)), 2) AS average
FROM PHY_VOTE t0
GROUP BY  t0.TITLE

如何使用条件创建查询

1 个答案: