SQL not showing just one product instead of more - mysql

Question

$query_sub = "SELECT * FROM `product_mappings` LEFT JOIN `product_list` ON `product_mappings`.ID_PRODUCT =`product_list`.ID WHERE ID_USER='" . $row{'ID'} . "'";
$result_sub = mysql_query($query_sub);
if ($result_sub && mysql_num_rows($result_sub) > 0)
{
$data_products = array();
while ($row_sub = mysql_fetch_array($result_sub))
{
$data_sub = array();
$data_sub["ID"] = $row_sub{'ID'};
$data_sub["product"] = $row_sub{'PRODUCT'};
$query_sub_unactive = "SELECT * FROM `product_list` WHERE ID != '" . $row_sub{'ID'} . "' ";
$result_sub_unactive = mysql_query($query_sub_unactive);
if ($result_sub_unactive && mysql_num_rows($result_sub_unactive) > 0)
{
$data_products_unactive = array();
while ($row_sub_unactive = mysql_fetch_array($result_sub_unactive))
{
$data_sub_unactive = array();
$data_sub_unactive["ID"] = $row_sub_unactive{'ID'};
$data_sub_unactive["productss"] = $row_sub_unactive{'PRODUCT'};
array_push($data_products_unactive, $data_sub_unactive);
}
$data_current["productsUnactive"] = $data_products_unactive;
}
array_push($data_products, $data_sub);
}
$data_current["products"] = $data_products;
Hi guys ! This is query where I should select only products that are not already in main query. I am checking if ID is the same as you can see. For example I load 4 products (of 15) with main query and unactive should load 11 of items in this case.. but loads 14 items.. so it "removes" just one product from list. Any clue?
Thanks !

Answer 1

SELECT * FROM `product_list` WHERE ID != '" . $row_sub{'ID'} . "' ";
This query is checking 1 ID at a time and is always going to return the other 14 rows. What you need is a "NOT IN" query like this:
SELECT * FROM `product_list` WHERE ID NOT IN ("id1","id2","id3","id4");