这是我的疑问：

SELECT
    `users`.`id` AS userID,
    `user_tests`.`id`,
    `users`.`profilePic`,
    `users`.`firstName`,
    `user_tests`.`userId`,
    `user_tests`.`isFirstAttempt`,
    `user_tests`.`total_marks`,
    FIND_IN_SET(
        `user_tests`.`total_marks`,
        (
        SELECT
            GROUP_CONCAT(
                DISTINCT `user_tests`.`total_marks`
            ORDER BY
                CAST(
                    `user_tests`.`total_marks` AS DECIMAL(5, 3)
                )
            DESC
            )
        FROM
            `user_tests`
        WHERE
            `user_tests`.`testSeriesId` = '856' AND `user_tests`.`isFirstAttempt` = '1'
    )
    ) AS rank,
FROM
    `user_tests`
LEFT JOIN `users` ON `users`.id = `user_tests`.`userId`
WHERE
    `user_tests`.`isFirstAttempt` = '1' AND `user_tests`.`testSeriesId` = '856'
ORDER BY
    CAST(
        `user_tests`.`total_marks` AS DECIMAL(5, 3)
    )
DESC
    ,
    `submissionTimeInMinutes` ASC,
    `rank` ASC;

输出量：
this is the image
预期值：
Here is the expected output image
我使用的是MariaDB 5.5.68，我尝试过使用变量来递增，但它显示的是当前行号，而不是1，2，3，4，5 ...数字。
有人能帮忙吗？谢谢。