我尝试使用这些模式进行简单的聊天:
mes_id int(10) unsigned Auto Increment
mes_useid_receiver int(10) unsigned
mes_useid_sender int(10) unsigned
mes_date int(10) unsigned
mes_message text
mes_read tinyint(3) unsigned [0]
mes_visible_for_who int(10) unsigned NULL NULL = both; 0 = none; ID user
问题是,如何获取已接收消息和已发送消息的联系人列表?
我正在尝试这样的事情:
SELECT use_name, MAX(mes_date) AS date
FROM message JOIN user ON mes_useid_receiver=use_id
WHERE uti_id!=1
AND (mes_useid_receiver=1 OR mes_useid_sender=1)
AND (mes_visible_for_who IS NULL OR mes_visible_for_who=1)
GROUP BY use_id
ORDER BY date DESC
但是通过这个查询,我只能得到向 user_id = 1
发送消息的联系人,我还想得到 user_id = 1 的联系人 已发送消息。
已编辑:
有了 union 我几乎可以得到我想要的:
SELECT use_id, use_name, mes_read FROM message
JOIN user ON mes_useid_receiver=use_id
WHERE use_id!=1
AND (mes_useid_receiver=1 OR mes_useid_sender=1)
AND (mes_visible_for_who IS NULL OR mes_visible_for_who=1) GROUP BY use_id
UNION
SELECT use_id, use_name, mes_read FROM message
JOIN user ON mes_useid_sender=use_id
WHERE use_id!=1
AND (mes_useid_receiver=1 OR mes_useid_sender=1)
AND (mes_visible_for_who IS NULL OR mes_visible_for_who=1) GROUP BY use_id
我需要 mes_date 来对列表进行排序,但如果我选择 mes_date,我将得到重复的行。
感谢您的帮助。
最佳答案
如果你要进入这个根目录,那么我的建议如下:
SELECT * FROM(
(SELECT use_id, use_name, mes_read ,mes_date FROM message
JOIN user ON mes_useid_receiver=use_id
WHERE use_id!=1
AND (mes_useid_receiver=1 OR mes_useid_sender=1)
AND (mes_visible_for_who IS NULL OR mes_visible_for_who=1)) GROUP BY use_id
UNION
(SELECT use_id, use_name, mes_read ,mes_date FROM message
JOIN user ON mes_useid_sender=use_id
WHERE use_id!=1
AND (mes_useid_receiver=1 OR mes_useid_sender=1)
AND (mes_visible_for_who IS NULL OR mes_visible_for_who=1)) GROUP BY use_id
) as d Order By mes_date desc
也看看你是否可以避免在每个选择中分组(你会觉得表现不佳)
问候
关于php - 用于一对一简单聊天的 MySQL 数据库模式,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/47825981/