Query running in PHPmyadmin but not through PHP - php

Question

I am trying to run a query from PHP which is not running but I can run the query from within phpMyAdmin
here is the code
<?php
ob_start();
//Delete Item question to admin and delete product
include"../storescripts/connect_to_mysql.php";
$conn = mysql_connect("$db_host","$db_username","$db_pass","$db_name") or die ("could not connect to mysql");
if (isset($_GET['deleteid'])) {
echo 'Do you really want to delete the item with ID '.$_GET['deleteid'].' ?Yes|No';
exit();
}
if(isset($_GET['yesdelete'])){
// Delete the actual product and delete picture also
//delete from database
$id_to_delete = $_GET['yesdelete'];
$manager=preg_replace('#[^A-Za-z0-9]#i','',$_GET['yesdelete']);
//$sql=mysql_query("SELECT id FROM admin WHERE username = '$manager' AND password='$password' LIMIT 1 ");
$sql = mysql_query( $conn ,"DELETE FROM products WHERE id=`$id_to_delete` LIMIT 1 ") or (mysql_error());
//echo 'The data at number ' . $id_to_delete . ' Deleted Sucessfully';
//mysqli_query("DELETE * FROM products WHERE id=`$id_to_delete`LIMIT1");// or (mysql_error());
//Unlink file from server
$pictodelete=("../inventory_images/$id_to_delete");
//echo $pictodelete;
if(file_exists($pictodelete)){
unlink($pictodelete);
}
// header("location:inventory_list.php");
//exit();
}
?>
I am new to PHP so your help is sought, i am able to connect to to database at another instance the code of which is following
<?php
//checking the user
ob_start();
session_start();
if (!isset($_SESSION["manager"])){
header ("location:admin_login.php");
exit();
}
//be sure to check if this manager SESSION value is in the database
$managerID=preg_replace('#[^0-9]#i','',$_SESSION["id"]);
$manager=preg_replace('#[^A-Za-z0-9]#i','',$_SESSION["manager"]);
$password=preg_replace('#[^A-Za-z0-9]#i','',$_SESSION["password"]);
//runMYSQL query to assertain that this is manager
//Connect to mysql database
include"../storescripts/connect_to_mysql.php";
$sql=mysql_query("SELECT*FROM admin WHERE id='$managerID' AND username='$manager' AND password='$password'LIMIT 1");
// make sure person exists in database
$existCount=mysql_num_rows($sql);
if ($existCount== 0)
{
echo "your data do not match our records";
exit();
}
?>
The code in connect_to_my_sql.php is as follows
<?php
/*
1: "die()" will exit the script and show an error statement if something goes wrong with the "connect" or "select" functions.
2: A "mysql_connect()" error usually means your username/password are wrong
3: A "mysql_select_db()" error usually means that the database does not exist
*/
// Place db host name Sometimes "localhost" but
// sometimes looks like this:>> ???mysql??.someserver.net
$db_host = "localhost";
//Place the username for the MySQL database here
$db_username = "storeuser";
//Place the password for the MySQL database here
$db_pass = "rajjar";
//Place the name for the MySQL database here
$db_name="mystore";
// Run the actual connection here
$conn = mysql_connect("$db_host","$db_username","$db_pass","$db_name") or die ("could not connect to mysql");
//mysql_select_db("$db_name") or die ("no database");
?>