Count the Prominence (m) of Col (m) smaller than 0?
CREATE TABLE "list_of_ultras_of_africa" (
  "peak" text,
  "country" text,
  "elevation_m" real,
  "prominence_m" real,
  "col_m" real
);
SELECT AVG("prominence_m") FROM "list_of_ultras_of_africa" WHERE "col_m"<0;