What could be causing the "supplied argument is not a valid MySQL result resource" error in the PHP code?

The error "supplied argument is not a valid MySQL result resource" typically occurs when trying to use a MySQL result resource that is not valid, often due to a failed query execution or incorrect handling of the result. To solve this issue, make sure that the query is executed successfully and the result is stored in a valid resource before using it in any further operations.

// Assuming $connection is a valid MySQL connection object
$query = "SELECT * FROM table_name";
$result = mysqli_query($connection, $query);

if($result){
    // Process the result
    while($row = mysqli_fetch_assoc($result)){
        // Do something with the data
    }
} else {
    echo "Error: " . mysqli_error($connection);
}