Mysql 在多个字段上使用GROUP_CONCAT

下面是我的数据库结构图：

在这里的用户帮助下，我使用

GROUP\u CONCAT

，成功地组合了一个相当复杂的SQL语句：

SELECT
     t1.Name AS Teacher_Name,
     t2.Name AS Observer_Name,
     o.Datetime AS Datetime,
     o.Type AS Type,
     o.Year_Group AS Year_Group,
     o.Class_Name AS Class_Name,
     c.Title AS Course_Name,
     GROUP_CONCAT(l.Title) AS Focus,
     o.Achievement_Grade AS Achievement_Grade,
     o.Behaviour_Grade AS Behaviour_Grade,
     o.Teaching_Grade AS Teaching_Grade,
     GROUP_CONCAT(cl1.Title) AS Positive,
     GROUP_CONCAT(cl2.title) AS Development,
     o.Notes AS Notes
FROM observations o
LEFT JOIN teachers t1 
    ON o.Teacher_ID = t1.Teacher_ID
LEFT JOIN teachers t2 
    ON o.Observer_ID = t2.Teacher_ID
LEFT JOIN courses c 
    ON o.Course_ID = c.Course_ID
LEFT JOIN  foci f
    ON o.ID = f.Observation_ID
LEFT JOIN focus_labels l
    on f.focus_id = l.id
LEFT JOIN  criteria c1
    ON o.ID = c1.Observation_ID
LEFT JOIN criteria_labels cl1
    on c1.Criteria_ID = cl1.ID AND c1.Type = 'P'
LEFT JOIN  criteria c2
    ON o.ID = c2.Observation_ID AND c2.Type = 'D'
LEFT JOIN criteria_labels cl2
    on c2.Criteria_ID = cl2.ID
GROUP BY o.id
ORDER BY `Datetime` DESC";

这似乎工作正常，除了

Focus

、

Positive

和

Development

都是重复的，这取决于在中具有最高串联数的字段

例如，如果

积极

具有

速度、进度、成就

，但

焦点

仅为

评估

，则将重复三次（

评估、评估、评估

）

我已经查过了，我想可能是因为我需要对每个

组连接进行
分组。然而，我不知道该怎么做

有人能帮忙吗？提前感谢，
具有可应用于删除重复项的独特属性

SELECT
     t1.Name AS Teacher_Name,
     t2.Name AS Observer_Name,
     o.Datetime AS Datetime,
     o.Type AS Type,
     o.Year_Group AS Year_Group,
     o.Class_Name AS Class_Name,
     c.Title AS Course_Name,
     GROUP_CONCAT(DISTINCT l.Title) AS Focus,
     o.Achievement_Grade AS Achievement_Grade,
     o.Behaviour_Grade AS Behaviour_Grade,
     o.Teaching_Grade AS Teaching_Grade,
     GROUP_CONCAT(cl1.Title) AS Positive,
     GROUP_CONCAT(cl2.title) AS Development,
     o.Notes AS Notes
FROM observations o
LEFT JOIN teachers t1 
    ON o.Teacher_ID = t1.Teacher_ID
LEFT JOIN teachers t2 
    ON o.Observer_ID = t2.Teacher_ID
LEFT JOIN courses c 
    ON o.Course_ID = c.Course_ID
LEFT JOIN  foci f
    ON o.ID = f.Observation_ID
LEFT JOIN focus_labels l
    on f.focus_id = l.id
LEFT JOIN  criteria c1
    ON o.ID = c1.Observation_ID
LEFT JOIN criteria_labels cl1
    on c1.Criteria_ID = cl1.ID AND c1.Type = 'P'
LEFT JOIN  criteria c2
    ON o.ID = c2.Observation_ID AND c2.Type = 'D'
LEFT JOIN criteria_labels cl2
    on c2.Criteria_ID = cl2.ID
GROUP BY o.id
ORDER BY `Datetime` DESC";