CREATE TABLE "by_density" (
  "rank" text,
  "state" text,
  "population" real,
  "area_km" real,
  "density" real
);

Question: What population has an area (km²) of 62,848 and a density less than 37.7?
SQL: SELECT COUNT("population") FROM "by_density" WHERE "area_km"='62,848' AND "density"<37.7;

Question: Which population is the greatest, has a density of 20.3, and an area (km²) larger than 50,350?
SQL: SELECT MAX("population") FROM "by_density" WHERE "density"=20.3 AND "area_km">'50,350';

Question: The state of Aguascalientes has an area (km²) larger than 151,571 and a density greater than 80.9, what is the rank?
SQL: SELECT "rank" FROM "by_density" WHERE "area_km">'151,571' AND "density">80.9 AND "state"='aguascalientes';