数据库查询获取用户朋友阅读的通知

Question

我有两张通知表和一张friend_list表。一个通知tbale是指具有通知信息的人员创建并输入的信息，以及所有第二个标识哪个朋友已阅读通知。能够检索由用户创建的通知仅显示给用户的朋友。但是现在我想从名为notification read的第二张表中显示未读给用户朋友的通知。

我所做的查询（从通知+ FRIEND_LIST表）

$sql3=mysql_query("select n.*,f.friend_id,f.uid,f.status from notification n,friend_list f where f.uid='$id' and f.status='1' and n.title_text='Global Notification' and n.user_id in ('$id' , f.friend_id) and n.owner_user_id=f.friend_id order by n.time_stamp desc"); 

现在如何获得通知的朋友读？

第二个表是

uid (friend_id) 
notification_id 
is_read 

现在我想用我现有的查询来获取被朋友未读通知的查询。

Answer 1

让我们supose说：

• '$id'是用户加薪通知
• n.user_id的ID是提高通知
• n.owner_user_id用户是接收通知

查询是用户：

select 
    n.*,f.friend_id,f.uid,f.status 
from 
    notification n 
inner join 
    friend_list f 
     on n.owner_user_id=f.friend_id 
inner join 
    notification_read nr 
     on nr.notification_id = n.notification_id and 
      nr.uid = f.friend_id 
where 
    f.status='1' and 
    n.title_text='Global Notification' and 
    n.user_id = '$id' and 
    nr.is_read = 0 
order by n.time_stamp desc 

编辑由于新的OP评论。

Answer 2

试试这个：

SELECT n.*,f.friend_id,f.uid,f.status 
FROM notification n 
    INNER JOIN friend_list f 
     ON n.owner_user_id = f.friend_id 
    INNER JOIN second_table s 
     ON f.friend_id = s.uid AND 
      n.notification_id = s.notification_id 
WHERE f.uid='$id' AND 
     f.status='1' AND 
     n.title_text='Global Notification' AND 
     n.user_id IN ('$id' , f.friend_id) AND 
     s.is_read = 0 
ORDER BY n.time_stamp DESC;