DoytoQuery 聚合查询方案示例详解

@Target(FIELD)
@Retention(RUNTIME)
public @interface GroupBy {
}

@Entity(name = "t_score")
private class ScoreGroupByStudentView {
    @GroupBy
    private Long studentId;
    private Double avgScore;
}

SELECT student_id AS studentId, avg(score) AS avgScore FROM t_score GROUP BY student_id

public interface Having extends Serializable {
}

public interface AggregationQuery extends DoytoQuery {
    Having getHaving();
}

public interface DataQueryClient {
    // ...
    <V, Q extends AggregationQuery>
    List<V> aggregate(Q query, Class<V> viewClass);
}

create table t_student_score
(
    id          bigint generated by default as identity primary key,
    school_term varchar(100)   not null,
    subject     varchar(100)   not null,
    student_no  varchar(10)    not null,
    score       numeric(10, 2) not null,
    is_deleted  boolean        not null default false
);

@Data
@NoArgsConstructor
@AllArgsConstructor
@Entity(name = "t_student_score")
public class StudentScoreStatView {
    @SuppressWarnings("java:S116")
    @GroupBy
    private String school_term;
    @GroupBy
    private String subject;
    private Integer countScore;
    private Double minScore;
    private Double maxScore;
    private Double avgScore;
}

public class StudentScoreHaving implements Having {
    private Integer countGt;
}

public class StudentScoreStatViewQuery extends PageQuery implements AggregationQuery {
    private String schoolTermGe;
    private List<String> subjectIn;
    private Double scoreGe;
    private Boolean isDeleted;
    private StudentScoreHaving studentScoreHaving;
    @Override
    public Having getHaving() {
        return studentScoreHaving;
    }
}

@SpringBootTest
class StudentScoreStatTest {
    @Resource
    private DataQueryClient dataQueryClient;
    @Test
    void aggregateStudentScore() {
        StudentScoreStatViewQuery statQuery = StudentScoreStatViewQuery
                .builder()
                .schoolTermGe("2000")
                .subjectIn(Arrays.asList("Chinese", "Math", "English"))
                .scoreGe(60.)
                .isDeleted(false)
                .studentScoreHaving(StudentScoreHaving.builder().countGt(1).build())
                .sort("school_term,asc;subject,asc")
                .build();
        SqlAndArgs sqlAndArgs = RelationalQueryBuilder.buildSelectAndArgs(statQuery, StudentScoreStatView.class);
        assertThat(sqlAndArgs.getSql()).isEqualTo(
                "SELECT school_term, subject, count(score) AS countScore, min(score) AS minScore, " +
                        "max(score) AS maxScore, avg(score) AS avgScore " +
                        "FROM t_student_score " +
                        "WHERE school_term >= ? AND subject IN (?, ?, ?) AND score >= ? AND is_deleted = ? " +
                        "GROUP BY school_term, subject " +
                        "HAVING count(*) > ? " +
                        "ORDER BY school_term asc, subject asc");
        assertThat(sqlAndArgs.getArgs()).containsExactly("2000", "Chinese", "Math", "English", 60., false, 1);
        List<StudentScoreStatView> statList = dataQueryClient.aggregate(statQuery, StudentScoreStatView.class);
        assertThat(statList).hasSize(3)
                            .first().isEqualTo(new StudentScoreStatView("2022", "Chinese", 3, 85., 93., 89.));
    }
}