从两个不同的数据库连接表

$db=mysql_connect("localhost", "testuser1", "testuser1") or die(mysql_error()); 
$db2=mysql_connect("localhost", "testuser2", "testuser2", true) or die(mysql_error()); 
$dbname="database1"; 
$dbname2="database2";

mysql_select_db($dbname,$db) or die (mysql_error());
mysql_select_db($dbname2,$db2) or die (mysql_error());


 //this is for the product attributes
 $data = mysql_query("SELECT db.attribute_stock, db.options_values_sku
                                 FROM db.products_attributes 
                                 LEFT OUTER JOIN db2.oscomstock ON db.product_attributes.options_value_sku=db2.oscomstock.options_value_sku 
                             ") or die(mysql_error()); 
$db=mysql_connect("localhost", "testuser1", "te