CREATE TABLE "references" (
  "num" real,
  "city" text,
  "1981_census" real,
  "1991_census" real,
  "2001_census" real,
  "2010_est" real,
  "region" text
);

Question: How many 2010 estimations have been done in the city of Cremona?
SQL: SELECT COUNT("2010_est") FROM "references" WHERE "city"='Cremona';

Question: What's the 2001 census of the region of Abruzzo where the 1871 census is bigger than 51092.0?
SQL: SELECT MIN("2001_census") FROM "references" WHERE "region"='Abruzzo' AND "1981_census">51092.0;

Question: What's the 1991 census of the city of Carpi?
SQL: SELECT MAX("1991_census") FROM "references" WHERE "city"='Carpi';

Question: How many 2001 censuses are there on number 13?
SQL: SELECT COUNT("2001_census") FROM "references" WHERE "num"=13;

Question: What's the 1981 census of Livorno?
SQL: SELECT "1981_census" FROM "references" WHERE "city"='Livorno';