CREATE TABLE enzyme (id DECIMAL, name TEXT, location TEXT, product TEXT, chromosome TEXT, omim DECIMAL, porphyria TEXT)
CREATE TABLE medicine_enzyme_interaction (enzyme_id DECIMAL, medicine_id DECIMAL, interaction_type TEXT)
CREATE TABLE medicine (id DECIMAL, name TEXT, trade_name TEXT, fda_approved TEXT)

How many different FDA approval statuses exist for medicines?
SELECT COUNT(DISTINCT fda_approved) FROM medicine
SELECT COUNT(DISTINCT "fda_approved") FROM "medicine"