CREATE TABLE MEDIATYPE (MediaTypeId VARCHAR, Name VARCHAR)
CREATE TABLE TRACK (MediaTypeId VARCHAR)

How many tracks are in the AAC audio file media type?
SELECT COUNT(*) FROM MEDIATYPE AS T1 JOIN TRACK AS T2 ON T1.MediaTypeId = T2.MediaTypeId WHERE T1.Name = "AAC audio file"
SELECT COUNT(*) FROM "MEDIATYPE" AS "T1" JOIN "TRACK" AS "T2" ON "T1"."MediaTypeId" = "T2"."MediaTypeId" WHERE "AAC audio file" = "T1"."Name"