CREATE TABLE mill (type VARCHAR, architect_id VARCHAR)
CREATE TABLE architect (Id VARCHAR)

What are the distinct types of mills that are built by American or Canadian architects?
SELECT DISTINCT T1.type FROM mill AS T1 JOIN architect AS t2 ON T1.architect_id = T2.Id WHERE T2.nationality = 'American' OR T2.nationality = 'Canadian'
SELECT DISTINCT "T1"."type" FROM "mill" AS "T1" JOIN "architect" AS "t2" ON "T1"."architect_id" = "T2"."Id" WHERE "T2"."nationality" = 'American' OR "T2"."nationality" = 'Canadian'