Database: superhero (difficulty: simple)
Question: Which superheroes have blue eyes with Black/Blue hair?
SQL: SELECT T1.superhero_name FROM superhero AS T1 INNER JOIN colour AS T2 ON T1.eye_colour_id = T2.id INNER JOIN colour AS T3 ON T1.hair_colour_id = T3.id WHERE T2.colour = 'Blue' AND T3.colour = 'Black/Blue'