Having trouble getting my mysql table to update - php

Question

This is the form I use to edit my table:
<?php
// get value of id that sent from address bar
$id=$_GET['id'];
// Retrieve data from database...
$sql = "SELECT * FROM chart WHERE id='$id'";
$result = $conn->query($sql);
// Output the loop...
if ($result->num_rows > 0) {
// output data of each row
while($row = $result->fetch_assoc()) { ?>
<form action="./include/update.php" method="post">
<tbody>
<tr>
<td><input type="date" id="date" name="date" value="<?php echo $row['date']; ?>" /></td>
<td><input type="text" id="nuvolog_am" name="nuvolog_am" value="<?php echo $row['nuvolog_am']; ?>" /></td>
<td><input type="text" id="nuvolog_noon" name="nuvolog_noon" value="<?php echo $row['nuvolog_noon']; ?>" /></td>
<td><input type="text" id="nuvolog_pm" name="nuvolog_pm" value="<?php echo $row['nuvolog_pm']; ?>" /></td>
<td><input type="text" id="predisone" name="predisone" value="<?php echo $row['predisone']; ?>" /></td>
<td><input type="text" id="norvase" name="norvase" value="<?php echo $row['norvase']; ?>" /></td>
<tr>
<td colspan="17"><input type="text" id="symptoms" name="symptoms" value="<?php echo $row['symptoms']; ?>" /></td>
</tr>
</tbody>
<tfoot>
<tr>
<td colspan="17"><input type="submit" value="Add Records"></td>
</tr>
</tfoot>
</form>
<? }
} else {
echo "0 results";
}
// Close the connection...
mysqli_close($link);
?>
And this is the update.php
<?php
// Database credentials...
$servername = "localhost";
$username = "...";
$password = "...";
$dbname = "...";
// Database connection...
$conn = new mysqli($servername, $username, $password, $dbname);
// Check the connection...
if($link === false){
die("ERROR: Could not connect. " . mysqli_connect_error());
}
// update data in mysql database
$sql="UPDATE chart SET
id = '$id',
date = '$date',
nuvolog_am = '$nuvolog_am',
nuvolog_noon = '$nuvolog_noon',
nuvolog_pm = '$nuvolog_pm',
predisone = '$predisone',
norvase = '$norvase'
WHERE id='$id'";
$result=mysql_query($sql);
// When chart is submitted...
if ($conn->query($sql) === TRUE) {
echo "Record updated successfully";
} else {
echo "Error updating record: " . $conn->error;
}
// Close the connection...
mysqli_close($link);
?>
It's probably something very simple, but I cannot figure out why this won't update the records database. I'm hoping somebody can help me figure this out.

Answer 1

Please replace $result=mysql_query($sql); to mysqli code.
like
$sql = "UPDATE MyGuests SET lastname='Doe' WHERE id=2";
$conn->query($sql);

Answer 2

to run query use this
$conn->query($sql);

Answer 3

You are updating the table using $result=mysql_query($sql); while to connect you used $conn = new mysqli($servername, $username, $password, $dbname);
By the way you should delete this question (if it's possible) or change all your passwords if the password that appears in the old version is used for other accounts too (you can see the edit history).