I want to know how many types of X are in the system

You have a thousands of products in your range but suspect most don't sell. You want a list of product-types that are in your orders list.

Solution

You can GROUP BY the product-code and sum quantity if you want to know that, or use count(distinct <field>)ref.

Discussion

In practice, you will probably want to see how many of each product you've sold.

SELECT ord_product, sum(ord_qty) FROM orders GROUP BY ord_product;
   

If you don't you can use

SELECT count(distinct ord_product) FROM orders;
   

This ignores null values of ord_product and throws away duplicates.