drug_sales(product_id, manufacturer, sales)

Return each manufacturer's total sales rounded to the nearest million, as manufacturer and total_sales_millions, highest first, breaking ties by manufacturer.

Sum first and round once at the end. Rounding each product before adding them up gives a different answer.

Tables

drug_sales

product_id  manufacturer  sales
----------  ------------  ----------
1           Acme          600000.00
2           Acme          600000.00
3           Acme          600000.00
4           Borne         5400000.00
5           Cole          2500000.00

Expected result

manufacturer  total_sales_millions
------------  --------------------
Borne         5
Cole          3
Acme          2