CREATE TABLE mountain (id NUMBER, name CLOB, height NUMBER, prominence NUMBER, range CLOB, country CLOB)
CREATE TABLE photos (id NUMBER, camera_lens_id NUMBER, mountain_id NUMBER, color CLOB, name CLOB)
CREATE TABLE camera_lens (id NUMBER, brand CLOB, name CLOB, focal_length_mm NUMBER, max_aperture NUMBER)

How many distinct kinds of camera lenses are used to take photos of mountains in the country 'Ethiopia'?
SELECT COUNT(DISTINCT T2.camera_lens_id) FROM mountain AS T1 JOIN photos AS T2 ON T1.id = T2.mountain_id WHERE T1.country = 'Ethiopia'
SELECT COUNT(DISTINCT "T2"."camera_lens_id") FROM "mountain" "T1" JOIN "photos" "T2" ON "T1"."id" = "T2"."mountain_id" WHERE "T1"."country" = 'Ethiopia'