What is the average lap total for grids under 19 and a Time/Retired of +4 laps?
CREATE TABLE "race" (
  "driver" text,
  "constructor" text,
  "laps" real,
  "time_retired" text,
  "grid" real
);
SELECT AVG("laps") FROM "race" WHERE "time_retired"='+4 laps' AND "grid"<19;