What is Craig Whelihan's average when his yards are smaller than 0?
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"='craig whelihan' AND "yards"<0;