Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE Order_items ( product_id VARCHAR, order_id VARCHAR )
TABLE: CREATE TABLE Products ( product_name VARCHAR, product_id VARCHAR )
TABLE: CREATE TABLE Orders ( order_id VARCHAR )

### Question ###
Show all product names and the number of customers having an order on each product.

### Accurate SQL ###

SELECT T2.product_name, COUNT(*) FROM Order_items AS T1 JOIN Products AS T2 ON T1.product_id = T2.product_id JOIN Orders AS T3 ON T3.order_id = T1.order_id GROUP BY T2.product_name