What is the average FL Cup Apps, with a FL Cup Goals greater than 0, but a Other Apps less than 0?
CREATE TABLE "sheffield_united_career" (
  "division" text,
  "league_apps_sub" real,
  "league_goals" real,
  "fa_cup_apps_sub" text,
  "fa_cup_goals" real,
  "fl_cup_apps_sub" real,
  "fl_cup_goals" real,
  "other_apps" real,
  "other_goals" real,
  "total_apps_sub" text,
  "total_goals" real
);
SELECT AVG("fl_cup_apps_sub") FROM "sheffield_united_career" WHERE "fl_cup_goals">0 AND "other_apps"<0;