What are the average net yards that have 9 as the touchdowns, 145 as the attempts, and yards per attempt greater than 4.8?
CREATE TABLE "rushing" (
  "player" text,
  "attempts" real,
  "net_yards" real,
  "yards_per_attempt" real,
  "touchdowns" real
);
SELECT AVG("net_yards") FROM "rushing" WHERE "touchdowns"=9 AND "attempts"=145 AND "yards_per_attempt">4.8;