不好意思，想請問一下，
這是我想做的表單，我想要輸入成績之後存到欄位對應的學號，
但不知道為甚麼只會存到第一筆 S0003 的成績， S0004 不會存到。
請問我該如何解決這個問題？
這是我目前的程式碼：

<?php
    session_start();
	$id=$_SESSION['user'];
	
    $servername = "localhost";
    $username = "root";
    $password = "";
    $dbname = "teacher";

    $conn = mysqli_connect($servername, $username, $password, $dbname);

    if (!$conn) {
        die("Connection failed: " . mysqli_connect_error());
    }
	
    $sql = "SELECT * FROM 課程表 WHERE 任課老師='$id'";
    $result = mysqli_query($conn, $sql);
	
    if (mysqli_num_rows($result) > 0) {
		echo "<form method='GET'>";
		echo "<select name = '課號'>";
		echo "<option disabled>請選擇課號</option>";
        while($row = mysqli_fetch_assoc($result)) {
            echo "<option>".$row["課號"]."</option>";
        }
		echo "</select>";
		echo "<input type='submit' value='確認'>";
		echo "</form>";
    }
	else {
        echo "<p>尚未教授任何課程</p>";
    }
	mysqli_close($conn);
?>
<?php
    if(isset($_GET['課號'])){
		$cID=$_GET['課號'];
		$servername = "localhost";
		$username = "root";
		$password = "";
		$dbname = "student";

		$conn = mysqli_connect($servername, $username, $password, $dbname);
		
		if (!$conn) {
			die("Connection failed: " . mysqli_connect_error());
		}
				
		$sql = "SELECT * FROM `成績表` WHERE `課號` = '$cID'";
		$result = mysqli_query($conn, $sql);
		$result = $conn->query($sql);
		if (mysqli_num_rows($result) > 0) {
			echo "<form method='POST'>";
			echo "<br><TABLE BORDER='1'>";
			echo "<TR ALIGN='CENTER'>";
			echo "<th>課號</th>";
			echo "<th>學號</th>";
			echo "<th>成績</th>";
			echo "</TR>";
			$count=0;
			while($row = mysqli_fetch_assoc($result)){	
	            echo "<TR ALIGN='CENTER'>";
				echo "<TD>".$row["課號"]."</TD>";
				echo "<TD>".$row["學號"]."</TD>";
				$score[$count]=$row["學號"];
				echo "<input type='hidden' size=10 name='cID' required='required' value='$cID'/>";
				echo "<TD><input type='text' name='$score[$count]' value='".$row["分數"]."' size=1/></TD>";
				echo "</TR>";
				$count++;
			}
			echo "</table><br>";
			echo "<input type='submit' value='送出'/>";
			echo "</form>";
        }
		else{
			echo "<p>還沒有任何學生修該堂課程！</p>";
		}
		mysqli_close($conn);
	}
?>
<?php
    if(isset($_POST['cID'])){
		$servername = "localhost";
		$username = "root";
		$password = "";
		$dbname = "student";
		$conn = mysqli_connect($servername, $username, $password, $dbname);
		
		if (!$conn) {
			die("Connection failed: " . mysqli_connect_error());
		}
		$cID=$_POST['cID'];
		for($i=0;$i<$count;$i++){
		    if(isset($_POST[$score[$i]])){
				$sID = $score[$i];
				$score = $_POST[$sID];
				$conn = mysqli_connect($servername, $username, $password, $dbname);
				if (!$conn) {
					die("Connection failed: " . mysqli_connect_error());
				}				
				$sql = "UPDATE `成績表` SET `分數` = '$score' WHERE `課號` = '$cID' AND `學號` = '$sID'";
				$result = mysqli_query($conn, $sql);
				$result=$conn->query($sql);
			}
		}
		echo '<meta http-equiv="refresh" content="0;">';
		mysqli_close($conn);
	}
?>

更新：
找到錯誤了QQ"
我耍蠢了$score = $POST[$sID]這段把$score取代掉了
已解決