Question

我正在尝试从我的表ptb_messages获取用户拥有的新消息数量，其中'read'设置为'0'

有人可以告诉我我哪里出错了。

我的表格如下：

id | from_user_id | to_user_id | subject | content | date_sent | read

1         2              4        hello     hello    2012-04-13    0

我正在使用此功能尝试显示用户拥有的未读消息数。

function check_new_messages() {
            global $connection;
            global $_SESSION;
            $query = "SELECT COUNT('read') FROM ptb_messages WHERE to_user_id =".$_SESSION['user_id']." AND ('read)'='0'";
            $check_new_messages_set = mysql_query($query, $connection);
            confirm_query($check_new_messages_set);
            return $check_new_messages_set;     
        }

<?php

$check_new_messages_set = check_new_messages();
while ($new = mysql_fetch_array($check_new_messages_set)) {

echo "There are ". $new['COUNT(read)'] ." items.";

}

 ?>

Answer 1

根本不需要COUNT那个字段; WHERE就够了。报价只是一点点就是：

$query = "SELECT COUNT(*) FROM ptb_messages WHERE to_user_id =".$_SESSION['user_id']." AND `read` = 0";

此外，请不要使用mysql_扩展名;它们在PHP 5.5中被弃用，并且很容易引入SQL注入漏洞。准备好PDO或MySQLi语句吧！

Answer 2

尝试：

        $query = "SELECT COUNT(read) FROM ptb_messages WHERE to_user_id =".$_SESSION['user_id']." AND read = 0";

您可能还想阅读SQL Injection。

Answer 3

首先，我认为您的SQL可能需要调整：

SELECT COUNT('read') FROM ptb_messages WHERE to_user_id =".$_SESSION['user_id']." AND ('read)'='0'

不应该是：

SELECT COUNT(id) FROM ptb_messages WHERE to_user_id =".$_SESSION['user_id']." AND `read` = 0

然后这一行：

echo "There are ". $new['COUNT(read)'] ." items.";

应该是：

echo "There are ". $new[0] ." items.";

Answer 4

好的，你确实需要查看Mysqli或PDO，据说，很明显你会有不同状态的列“读”.0 =未读，1 =读等等....

在这里，您可以使您的功能更通用，并允许您通过一个功能获得这些状态。像这样：

function check_new_messages($id,$state)
{
    $query ="SELECT COUNT(*)as newmessage FROM ptb_messages WHERE to_user_id =".$id." AND `read` ='".$state."'";
    $check_new_messages_set = mysql_query($query, $connection);
    confirm_query($check_new_messages_set);
    return $check_new_messages_set;     
 }
    $check_new_messages_set = check_new_messages($_SESSION['user_id'], '0' );
    while ($new = mysql_fetch_array($check_new_messages_set))
        {
            echo "There are ". $new['newmessage'] ." items.";
        }

以下是使用MYSQLI的示例。在此示例中，您可以返回行计数并回显它：

function check_new_messages($id,$state)
{
    $MessageCount = new mysqli(DB_HOST, DB_USERNAME, DB_PASSWORD, DB_NAME);
    if ($MessageCount->connect_errno)
    {
        echo "Failed to connect to MySQL: (" . $MessageCount->connect_errno . ") " . $MessageCount->connect_error;
        $MessageCount->close();
    }
    $values = $MessageCount->query("SELECT to_user_id FROM ptb_messages WHERE to_user_id =".$id." AND `read` ='".$state."'");
    if($count = $values->num_rows)
    {
        return $count;
    }
        return 0;
}

//像这样回电话

$Unread = check_new_messages($_SESSION['user_id'], '0' );
echo "There are ". $Unread ." items.";

使用COUNT函数计算新邮件数？

4 个答案: