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 products ( product_id VARCHAR )
TABLE: CREATE TABLE Order_items ( product_id VARCHAR )

### Question ###
How many products were not included in any order?

### Accurate SQL ###

SELECT COUNT(*) FROM products WHERE NOT product_id IN (SELECT product_id FROM Order_items)