H2 数据库：“U”列必须在 GROUP BY 列表中； SQL 语句

Question

我的原生查询如下所示：

SELECT u
FROM (SELECT max(difficulty), u
      FROM (SELECT sum(difficulty) AS difficulty, username AS u
            FROM user_answer ua
                     JOIN question q ON ua.question_id = q.id
                     JOIN answer a ON ua.answer_id = a.id
                     JOIN user_quiz uq ON ua.user_quiz_id = uq.id
                     JOIN account ac ON uq.account_id = ac.id
            WHERE a.correct = 1
              AND uq.quiz_start_date_time >= (CURDATE() - INTERVAL 7 DAY)
            GROUP BY ua.user_quiz_id
            ORDER BY difficulty DESC) AS max_week) as d_u

在 MySQL 中一切正常。我在 H2 数据库中有错误：

org.h2.jdbc.JdbcSQLSyntaxErrorException: Column "U" must be in the GROUP BY list; SQL statement:
SELECT u FROM (SELECT max(difficulty), u FROM (SELECT sum(difficulty) AS difficulty, username AS u FROM user_answer ua JOIN question q ON ua.question_id = q.id JOIN answer a ON ua.answer_id = a.id JOIN user_quiz uq ON ua.user_quiz_id = uq.id JOIN account ac ON uq.account_id = ac.id WHERE a.correct = 1 AND uq.quiz_start_date_time >= (CURDATE() - INTERVAL 7 DAY) GROUP BY ua.user_quiz_id ORDER BY difficulty DESC) AS max_week) as d_u [90016-200]

如何解决？

Answer 1

只需在用户名周围添加一个聚合函数

    SELECT u
    FROM (SELECT max(difficulty), u
          FROM (SELECT sum(difficulty) AS difficulty, MAX(username) AS u
                FROM user_answer ua
                         JOIN question q ON ua.question_id = q.id
                         JOIN answer a ON ua.answer_id = a.id
                         JOIN user_quiz uq ON ua.user_quiz_id = uq.id
                         JOIN account ac ON uq.account_id = ac.id
                WHERE a.correct = 1
                  AND uq.quiz_start_date_time >= (CURDATE() - INTERVAL 1 MONTH)
                GROUP BY ua.user_quiz_id
                ORDER BY difficulty DESC
            ) AS max_month
        GROUP BY u
        ) as d_u

启用 ONLY_FULL_GROUP_BY 选项后，您需要使所有列都具有聚合函数或将它们放在 GROUP By 中，参见https://dev.mysql.com/doc/refman/5.7/en/group-by-handling.html