mysql ：将其中两个数据的某一个字段合拼成一句

SELECT 
  xq.*,
  ts.xu_qiu_id,
  ts.content 
FROM
  wx_xu_qiu xq 
  LEFT JOIN 
    (SELECT 
      xu_qiu_id,
      GROUP_CONCAT(content) AS 'content' 
    FROM
      wx_track_status GROUP BY xu_qiu_id) AS ts 
    ON xq.id = ts.xu_qiu_id