CREATE TABLE "ranking" (
  "country" text,
  "population_july_2005_est" real,
  "land_area_km" real,
  "pct_of_arable_land_2005_est" text,
  "arable_land_km" real,
  "population_density_pop_per_km" real
);

Question: What is the total population of American Samoa (US) that has less than 16,280 km² arable land, less than 240 km² land area, and has a population density of more than 291?
SQL: SELECT COUNT("population_july_2005_est") FROM "ranking" WHERE "arable_land_km"<'16,280' AND "land_area_km"<240 AND "country"='american samoa (us)' AND "population_density_pop_per_km">291;

Question: What's the arable land for the population of 20,090,437?
SQL: SELECT MAX("arable_land_km") FROM "ranking" WHERE "population_july_2005_est"='20,090,437';

Question: What is the land area of Switzerland with a population density fewer than 188 km²?
SQL: SELECT AVG("land_area_km") FROM "ranking" WHERE "country"='switzerland' AND "population_density_pop_per_km"<188;

Question: What's the population density of the Democratic Republic of the Congo when the population is greater than 37,762,842, and the arable land is more than 200 km²?
SQL: SELECT "population_density_pop_per_km" FROM "ranking" WHERE "population_july_2005_est">'37,762,842' AND "arable_land_km">200 AND "country"='democratic republic of the congo';