If the manufacturer is Yamaha, and the laps driven were under 32, what's the average of all grid sizes with that criteria?
CREATE TABLE "moto_gp_classification" (
  "rider" text,
  "manufacturer" text,
  "laps" real,
  "time" text,
  "grid" real
);
SELECT AVG("grid") FROM "moto_gp_classification" WHERE "laps"<32 AND "manufacturer"='yamaha';