mysql将时间字段转换为几天前、几小时前、几分钟前

SELECT 
n.id,
CASE 
WHEN TIMESTAMPDIFF(DAY, n.chuangjiansj,NOW()) > 0 
THEN CONCAT(TIMESTAMPDIFF(DAY, n.chuangjiansj,NOW()),'天前')

WHEN TIMESTAMPDIFF(HOUR, n.chuangjiansj,NOW()) > 0 
THEN CONCAT(TIMESTAMPDIFF(HOUR, n.chuangjiansj,NOW()),'小时前')

WHEN TIMESTAMPDIFF(MINUTE, n.chuangjiansj,NOW()) > 0 
THEN CONCAT(TIMESTAMPDIFF(MINUTE, n.chuangjiansj,NOW()),'分钟前')
ELSE  '未知时间'
END AS time
FROM flow_notice n