Question

我在我的应用程序中使用了一个消息系统，我希望在他的配置文件中获取未读消息的数量，模式如下

Users table     message

user_id         message_id 
......          sender_id
                receiver id
                text 
                flag

标记用于确定用户是否已阅读消息的位置。 flag = 0用户未读取消息，1为读取

如何获取特定用户的未读消息数

SELECT message_id, count(*)
FROM message
WHERE flag=0
GROUP BY receiver_id;

Answer 1

你快到了，试试这个：

SELECT receiver_id, count(*) as unread_cnt
FROM message
WHERE flag = 0
AND receiver_id = '$particular_user_id'  // If you want all users, you can comment out this line.
GROUP BY receiver_id;

您也可以通过以下方式获得读数：

SELECT
    receiver_id,
    COUNT(CASE WHEN flag = 0 THEN receiver_id END) as unread_cnt,
    COUNT(CASE WHEN flag = 1 THEN receiver_id END) as read_cnt
FROM message
WHERE receiver_id = '$particular_user_id' // If you want all users, you can comment out this line.
GROUP BY receiver_id;

Answer 2

试试这个：

SELECT count(*) as count, message_id
FROM message
WHERE flag=0
GROUP BY receiver_id;

Php mysql未读用户的消息

2 个答案: