How many Games have Years at club of 1971–1974, and a Debut year larger than 1971?
CREATE TABLE "1970s" (
  "debut_year" real,
  "player" text,
  "games" real,
  "goals" real,
  "years_at_club" text
);
SELECT SUM("games") FROM "1970s" WHERE "years_at_club"='1971–1974' AND "debut_year">1971;