Question: What's the sum of the population for the place simplified 上杭县 with an area smaller than 2879?
SQL: SELECT SUM("Population") FROM "2-1204998-2" WHERE "Simplified" = '上杭县' AND "Area" < 2879.0;

Question: What's the total number of density for the place with a population over 393390?
SQL: SELECT COUNT("Density") FROM "2-1204998-2" WHERE "Population" > 393390.0;

Question: What's the average area for the Xinluo District?
SQL: SELECT AVG("Area") FROM "2-1204998-2" WHERE "English Name" = 'Xinluo District';