What is Mark Grieb's average when his TDs are smaller than 2?
CREATE TABLE "running_backs" (
  "player" text,
  "car" real,
  "yards" real,
  "avg" real,
  "td_s" real,
  "long" real
);
SELECT SUM("avg") FROM "running_backs" WHERE "player"='mark grieb' AND "td_s"<2;