mysql - 如何在 MySQL 中正确执行此有限分组查询？

Question

我有一个查询返回 25 名医生的列表，需要在列中反射(reflect)他们上传的文件 (cloud_uploads)。问题是，我不想限制列出的文件数量，但该限制似乎也适用于文件。我见过的其他类似问题有相反的问题 - 他们想限制文件而不限制返回的总行数。我的医生上传的文件超过 25 个，但列表仅显示前 25 个文件，而不是全部。

因为这是一个以编程方式生成的查询，所以我无法将其分成多个查询。它必须是一。所以，如果答案是做不到，我可以接受。

这是当前查询:

SELECT SQL_CALC_FOUND_ROWS records.instance_id,
        instances.patient_id,
        TRIM(form_1_data.field_2) AS field_0,
        TRIM(form_1_data.field_1) AS field_1,
        TRIM(form_1_data.field_87) AS field_2,
        GROUP_CONCAT(DISTINCT CONCAT (
                        extensible_8_data.field_953,
                        '|||',
                        cloud_uploads.NAME
                        ) SEPARATOR '<br />') AS field_3
FROM form_6_data AS records
LEFT JOIN instances
        ON instances.id = records.instance_id
LEFT JOIN extensible_8_data
        ON records.instance_id = extensible_8_data.instance_id
LEFT JOIN cloud_uploads
        ON extensible_8_data.field_953 = cloud_uploads.id
LEFT JOIN form_1_data
        ON records.field_89 = form_1_data.instance_id
WHERE instances.form_id = 6
        AND instances.active = 1
        AND (
                cloud_uploads.active = 1
                OR cloud_uploads.active IS NULL
                )
GROUP BY records.instance_id
ORDER BY records.instance_id DESC LIMIT 0, 25

Answer 1

加入一个子查询，选择 25 位感兴趣的医生及其文件:

SELECT SQL_CALC_FOUND_ROWS records.instance_id,
        instances.patient_id,
        TRIM(form_1_data.field_2)  AS field_0,
        TRIM(form_1_data.field_1)  AS field_1,
        TRIM(form_1_data.field_87) AS field_2,
        GROUP_CONCAT(DISTINCT CONCAT (
                        extensible_8_data.field_953,
                        '|||',
                        cloud_uploads.NAME
                        ) SEPARATOR '<br />') AS field_3
FROM (SELECT * FROM form_6_data ORDER BY instance_id DESC LIMIT 25) AS records
LEFT JOIN instances
        ON instances.id = records.instance_id
LEFT JOIN extensible_8_data
        ON records.instance_id = extensible_8_data.instance_id
LEFT JOIN cloud_uploads
        ON extensible_8_data.field_953 = cloud_uploads.id
LEFT JOIN form_1_data
        ON records.field_89 = form_1_data.instance_id
WHERE instances.form_id = 6
        AND instances.active = 1
        AND (
                cloud_uploads.active = 1
                OR cloud_uploads.active IS NULL
                )
GROUP BY records.instance_id
ORDER BY records.instance_id