PHP在数据库中的某个位置插入值

因此，我目前正在创建一个在线游戏，并且已经获得了登录和注册功能，但现在我正在提交诸如健康和玩家等级等统计数据并检索这些数据。 因此，在这个PHP文件中，我能够检索某个玩家的信息，但我不知道如何将新的统计数据提交到某个玩家的行中。我还在学习PHP，所以请帮助我

<?php
// Database Things =========================================================
$host = "localhost";
$user = "lyth_com_Spillnk";
$password = "INTERESTED?";
$dbname = "lythumn_com_Spillnk";
mysql_connect($host, $user, $password) or die("Can't connect into database");
mysql_select_db($dbname)or die("Can't connect into database");   
// =============================================================================
$Act = $_GET["Act"];// what is action, Submit or Retrieve?
$nick = $_GET["User"];
$health = $_GET["Health"];
$level = $_GET["Level"];
$xcood = $_GET["X"]; 
$ycood = $_GET["Y"];
if($Act == "Retrieve"){
        $SQL = "SELECT * FROM Stats WHERE Username = '" . $nick . "'";
        $result_id = @mysql_query($SQL) or die("DB ERROR");
        $total = mysql_num_rows($result_id);
        if($total) {
            $datas = @mysql_fetch_array($result_id);
            echo ($datas["Health"], $datas["Level"], $datas["X"], $datas["Y"]);
        }   
}
if($Act == "Submit"){
    $SQL = "SELECT * FROM Stats WHERE Username = '" . $nick . "'";
    $result_id = @mysql_query($SQL) or die("DB ERROR");

    $query = "INSERT INTO Stats (Username, Health, Level, X, Y) VALUES('$nick', '$health', '$level', $'xcood', $'ycood')";
    mysql_query($query) or die("ERROR");
    mysql_close();

    echo "Submitted";
}

// Close mySQL Connection
mysql_close();
?>

正如你所看到的，我已经检索到了球员统计数据所在的索引，那么我如何在那里插入值呢

---

提前谢谢

Mysql中有

UPDATE

语句可以帮助您。谢谢您解决了我的问题！

if($Act == "Submit"){
$SQL = "SELECT * FROM Stats WHERE Username = '" . $nick . "'";
$result_id = @mysql_query($SQL) or die("DB ERROR");

$query = "INSERT INTO Stats (Username, Health, Level, X, Y) VALUES('$nick', '$health', '$level', $'xcood', $'ycood')";
mysql_query($query) or die("ERROR");
mysql_close();

echo "Submitted";
}