How many HC climbs had 1 visit more recently than 1984, a first HC climb before 1994, and a height of 1900?
CREATE TABLE "tour_de_france" (
  "height_m" text,
  "no_of_times_visited" real,
  "no_of_hc_climbs" real,
  "first_time_as_hc_climb" real,
  "most_recent" real
);
SELECT "no_of_hc_climbs" FROM "tour_de_france" WHERE "no_of_times_visited"=1 AND "most_recent">1984 AND "first_time_as_hc_climb"<1994 AND "height_m"='1900';