What is the description of the color used by least products?
create table ref_colors (color_description varchar, color_code varchar, PRIMARY KEY (color_description)); create table products (color_code varchar, PRIMARY KEY (color_code))
select t2.color_description from products as t1 join ref_colors as t2 on t1.color_code = t2.color_code group by t2.color_description order by count(*) limit 1