CREATE TABLE manufacturer (manufacturer_id DECIMAL, open_year DECIMAL, name TEXT, num_of_factories DECIMAL, num_of_shops DECIMAL)
CREATE TABLE furniture_manufacte (manufacturer_id DECIMAL, furniture_id DECIMAL, price_in_dollar DECIMAL)
CREATE TABLE furniture (furniture_id DECIMAL, name TEXT, num_of_component DECIMAL, market_rate DECIMAL)

How many furniture components are there in total?
SELECT SUM(num_of_component) FROM furniture
SELECT SUM("num_of_component") FROM "furniture"