我的数据库结构：

人

id | name  |
1  | John  |
2  | Doe   |
3  | Marc  |

任务

task_id |  task_name| person_id
  1     |  Get milk |  1
  2     |   Play cs |  1
  3     |  Walk dog |  2
  4     | Eat fruit |  3

评论

id     | comment  | task
 1     | Which one |  1
 2     | When?    |  2

我已经试过了：

function get_shapes2() {  
    $this->db->select('person.name,person.id,')
    ->select('GROUP_CONCAT(DISTINCT comments.id  separator " -/r/- ") as "commentid" ')
    ->select('GROUP_CONCAT(DISTINCT comments.comment  separator " -/r/- ") as "comment" ')
    ->select('GROUP_CONCAT(DISTINCT tasks.task_name  separator " -/r/- ") as "tname"')
    ->select('GROUP_CONCAT(DISTINCT tasks.task_id separator " -/r/- " ) as "id2"');    
    $this->db->from('person');
    $this->db->join('tasks', 'tasks.person_id = person.id', 'left');
    $this->db->join('comments', 'comments.task = tasks.task_id', 'left ');        
    $this->db->group_by('id');
    $query = $this->db->get();
    $res = array();
    foreach ($query->result() as $row) {
        $posts[] = $row->name;
        $posts[] = (int) $row->id;
        $posts[] = array_map(function($tname, $tid){
             return array('tname'=>$name,'tid'=>$tid);
        },
        explode(" -/r/- ",$row->tname),
        explode(" -/r/- ",$row->id2));
        array_push($res, $posts);
        unset($posts);
    }
    return $res;
}

我得到的是：

{name: John,  id: 1, task =[ {tname: "Get milk", tid: "1"},{tname: "Play cs", tid: "2"}]}

我尝试做的是为每个人获取所有任务，如果comment存在，则仅获取1个最新的comment, comment_id，并将其存储在与任务相同的数组中

{name: John,  id: 1, task =[ {tname: "Get milk", tid: "1" comment: " Which one", commentid: 1 },{tname: "Play cs", tid: "2" comment: " When?", commentid: 2 }]}

我所面临的问题是我不知道该怎么做，我试过将它添加到array_map中，但它随机存储评论，似乎不起作用。