使用mysql_result PHP从MySQL迁移到MySQLi

Question

因此，最初，我知道使用MySQL扩展对安全性没有好处，并且没有进行更新，但我只是将其用于学习，但是现在我想转到MySQLi，但不确定如何转换。 我有两个问题，我不确定去哪儿，如下面第一组代码所示。

我想做的是检查服务器是否处于活动状态，并且在数据库中定义了该服务器，该表如下所示

因此，如果active等于1则为true ，否则为false 。

function server_active_query($data) {
    $server = sanitize($data);
    $query = mysql_query("SELECT COUNT(`server_id`) FROM `servers` WHERE `servername` = '$server' AND `active` = 1"); 
    return (mysql_result($query, 0) == 1) ? true: false;
}

//This is the new function so don't worry about the name
function server_active_query($data) {
    $dbc = new mysqli('db_host', 'db_user', 'db_pass', 'db_db');
    $server = sanitize($data, $dbc);
    $query = $dbc->query("SELECT COUNT(`s_id`) FROM `servers` WHERE `servername` = '$server' AND `active` = 1"); 
    //Not sure where to go from here as It does not work.
    return (mysqli_result($query, 0) == 1) ? true: false;
}

Answer 1

您需要坚持使用OO mysqli调用，而您正在寻找的是$ result-> num_rows，它返回SELECT查询返回的行数。

使用-> query（）返回一个mysqli_result对象，它不能像mysql_扩展那样从第0列返回数据，因此请更改查询以选择一个字段，因此仅在找到时返回一行处于活动状态的服务器，则可以使用->num_rows属性

function server_active_query($data) {
    $dbc = new mysqli('db_host', 'db_user', 'db_pass', 'db_db');
    $server = sanitize($data, $dbc);

    $result = $dbc->query("SELECT `s_id` 
                           FROM `servers` 
                           WHERE `servername` = '$server' AND `active` = 1"); 

    return $result->num_rows == 1 ? true: false;
}

还是使用更好的prepare（）样式

function server_active_query($data) {
    $dbc = new mysqli('db_host', 'db_user', 'db_pass', 'db_db');
    $server = sanitize($data, $dbc);

    $stmt = $dbc->prepare("SELECT s_id
                           FROM servers 
                           WHERE servername = ? 
                             AND active = 1"); 

    $stmt->bind_param("s", $server);
    if ( $stmt->execute() ) {
       $return = $stmt->num_rows == 1 ? true: false;
    } else {
       // error processing code or just default to false?
       $return = false
    }

    // as we have not actually processed the returned row 
    // we had better clean up the statement handle
    $stmt->close(); 

    return $return;
}