merhabalar Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given in hatasini almaktayim


Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given in /order/includes/wallet.php on line 4

Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given in /order/includes/wallet.php on line 8


sorun nedir acaba bilen biri yardimci olabilirmi

<?php
$user_id=$_SESSION['user_id'];
$sql = mysqli_query($con, "SELECT * FROM wallet where customer_id = $user_id");
while($row1 = mysqli_fetch_array($sql)){
$wallet_id = $row1['id'];
}
$sql = mysqli_query($con, "SELECT * FROM wallet_details where wallet_id = $wallet_id");
while($row1 = mysqli_fetch_array($sql)){
$balance = $row1['balance'];
}
?>