You forgot to call mysqli_query()
to perform the UPDATE
.
if (mysqli_query($conn, $sql1)) {
$sql2="UPDATE activations SET status='in use' WHERE code='$code'";
if (!mysqli_query($conn, $sql2)) {
echo "Error updating activations: " . mysqli_error($conn);
}
} else {
echo "Error inserting student: " . mysqli_error($conn);
}