diff --git a/htdocs/product/class/product.class.php b/htdocs/product/class/product.class.php
index dc9a08a24c7..b08ccb139ba 100644
--- a/htdocs/product/class/product.class.php
+++ b/htdocs/product/class/product.class.php
@@ -1803,8 +1803,9 @@ class Product extends CommonObject
                 $sql .= " ,pfp.multicurrency_price, pfp.multicurrency_unitprice, pfp.multicurrency_tx, pfp.fk_multicurrency, pfp.multicurrency_code";
 				if (!empty($conf->global->PRODUCT_USE_SUPPLIER_PACKAGING)) $sql .= ", pfp.packaging";
                 $sql .= " FROM ".MAIN_DB_PREFIX."product_fournisseur_price as pfp";
-                $sql .= " WHERE 1=1";
-                if ($product_id != 0) { $sql .= " AND pfp.fk_product = '".$product_id."'";
+                $sql .= " WHERE 1 = 1";
+                if ($product_id > 0) { 
+					$sql .= " AND pfp.fk_product = ".((int) $product_id);
                 }
                 if ($fourn_ref != 'none') { $sql .= " AND pfp.ref_fourn = '".$fourn_ref."'";
                 }