how do i solve this problem?
i have ["subgridparams"] = "invoice_id, customer_id";

how do i use customer id to work on this in my subgrid

$col = array();
$col["title"] = "Product";
$col["name"] = "product_c";
$col["dbname"] = "products.product_code"; // this is required as we need to search in name field, not id
$col["width"] = "30";
$col["align"] = "left";
$col["search"] = true;
$col["editable"] = true;
$col["editrules"] = array("required"=>true);
$col["formatter"] = "autocomplete"; // autocomplete
$col["formatoptions"] = array( "sql"=>"select distinct product_code as k, product_code as v from salesman_price WHERE customer_id = '$customer_id'",
"search_on"=>"product_code",
"update_field" =>"product_c"
);

$col["editoptions"] = array(

"onchange" => array(
"sql"=>"select product_code, product_description, quantity, weight, price from salesman_price WHERE customer_id = '$customer_id'",
"search_on"=>"product_code",
"callback" => "fill_form_add_sales" )
);
$cols[] = $col;