PHP connection and query error: Fatal error: Call to a member function query() on null in

Question

I'm getting the above error in regards to my statement below, tried multiple fixes from other answers in stack but continue to get the same error :(

this is part of a php code in a user registration form, would like their info to insert in the table

if($conn->query( "INSERT INTO users (FIRST_NAME, LAST_NAME, USERNAME, PASSWORD)
VALUES ('$fname', '$lname', '$uname', '$pword')")==TRUE){
 echo 'Inserted';
 }else{
 echo 'Not Inserted';
 }

i have this other code in a separate file for the $conn

function dbConnect(){
 $servername = "x";
 $database = "activity2"; 
 $username  = "root"; 
 $password = "root";
// Create connection
 $conn = new 
mysqli($servername, $username, $password, $database); 
// Check connection 
if  ($conn->connect_error) { die("Connection failed: " . $conn->connect_error); 
} //echo "Connection successful"; //make variable global to access in other 
functions global $conn; return $conn;} 

Answer 1

First thing to do is to create the class that will return a connection:

<?php
//filename: dbConnect.php
class dbConnect
{
	
		public function connect() {
			 global $conn;
				
			 $servername = "localhost";
			 $username  = "root"; 
			 $password = "";
			 $database = "test";  
			// Create connection
			 $conn = new mysqli($servername, $username, $password, $database); 
			// Check connection 
			if  ($conn->connect_error) { 
				die("Connection failed: " . $conn->connect_error); 
			} //echo "Connection successful"; //make variable global to access in other 
			
			return $conn;			
		}
}

?>

Now you can execute your sql command in another file:

<?php
require 'dbConnect.php';

	$db = new dbConnect();
	$conn = $db->connect();

	$nome = "Anailton";
	$email = "jose@hotmail.com";
	if($conn->query( "INSERT INTO clientes (NOME, EMAIL) VALUES ('$nome', '$email')")==TRUE){
		echo 'Inserted';
	}else{
		echo 'Not Inserted';
	}

?>