Fehlende variable Daten von SQL

Question

Ich habe die Daten von SQL aufgerufen und durch die ID ausgewählt, dann möchte ich die Daten aus "mysqli_fetch_array" row [1] verwenden, um eine Berechnung durchzuführen.

aber irgendwie in Zeile 14 kann die $ row [1] nicht das Datum für die Berechnung bekommen.

index.php

<?php 
$con = mysqli_connect('localhost','root','','test2'); 
$query = mysqli_query($con,"SELECT * FROM count") or 
die(mysqli_error($con)); 


while($row = mysqli_fetch_array($query)) 
    echo "$row[id]. $row[quantity] <a href='edit.php?edit=$row[id]'>Draw 
Patrs<br />"; 
?> 

edit.php

<?php 

if(isset($_GET['edit'])) 
{ 
    $id = $_GET['edit']; 
    $con = mysqli_connect('localhost','root','','test2'); 
    $query = mysqli_query($con,"SELECT * FROM count WHERE id='$id'"); 
    $row = mysqli_fetch_array($query); 
} 

if(isset($_POST['drawquantity'])) 
{ 
    $drawquantity = $_POST['drawquantity']; 
    $newquantity = $row[1]-$drawquantity; 
    $id  = $_POST['id']; 
    $sql  = "UPDATE count SET quantity='$newquantity' WHERE id='$id'"; 
    $con = mysqli_connect('localhost','root','','test2'); 
    $res  = mysqli_query($con,$sql) 
           or die("Could not update".mysql_error()); 
    echo "<meta http-equiv='refresh' content='0;url=index.php'>"; 

} 

?> 
<form action="edit.php" method="POST"> 
How mant you will take away: <input type="text" name="drawquantity" value="" 
placeholder="<?php echo $row[1]; ?>"><br /> 

<input type="hidden" name="id" value="<?php echo $row[0]; ?>"> 
<input type="submit" value=" Update "/> 
</form> 

Answer 1

<?php 

if(isset($_GET['edit'])) 
{ 
    $id = $_GET['edit']; 
    $con = mysqli_connect('localhost','root','','test2'); 
    $query = mysqli_query($con,"SELECT * FROM count WHERE id='$id'"); 
    $row = mysqli_fetch_array($query); 
} 

if(isset($_POST['drawquantity'])) 
{ 
    $drawquantity = $_POST['drawquantity']; 
    $newquantity = $row[1]-$drawquantity; 
    $id  = $_POST['id']; 
    $sql  = "UPDATE count SET quantity='$newquantity' WHERE id='$id'"; 
    $con = mysqli_connect('localhost','root','','test2'); 
    $res  = mysqli_query($con,$sql) 
          or die("Could not update".mysql_error()); 
    echo "<meta http-equiv='refresh' content='0;url=index.php'>"; 

} 

?> 
<form action="edit.php?edit=<?=$_GET['edit']?>" method="POST"> 
How mant you will take away: <input type="text" name="drawquantity" value="" 
placeholder="<?php echo $row[1]; ?>"><br /> 

<input type="hidden" name="id" value="<?php echo $row[0]; ?>"> 
<input type="submit" value=" Update "/> 
</form> 

Änderung Aktion ist