What team is from the United States and plays a guard position for the Grizzlies in 2012?
CREATE TABLE "a" (
  "player" text,
  "nationality" text,
  "position" text,
  "years_for_grizzlies" text,
  "school_club_team" text
);
SELECT "school_club_team" FROM "a" WHERE "nationality"='united states' AND "position"='guard' AND "years_for_grizzlies"='2012';