Table: naval_warships
Columns: warship
tons_l_ton
horse_power
speed_knots
armour_inch
main_artillery
built_year

Question: What's Blanco Encalada's main artillery?
SQL: SELECT "main_artillery" FROM naval_warships WHERE "warship" = 'Blanco Encalada'

Question: How many different horse-powers does the Cochrane have?
SQL: SELECT COUNT("horse_power") FROM naval_warships WHERE "warship" = 'Cochrane'

Question: What warship has horse-power of 1500?
SQL: SELECT "warship" FROM naval_warships WHERE "horse_power" = 1500

Question: How much does the Independencia weight?
SQL: SELECT MIN("tons_l_ton") FROM naval_warships WHERE "warship" = 'Independencia'

Question: In how many different years was the warship that weights 1130 tons built?
SQL: SELECT COUNT("built_year") FROM naval_warships WHERE "tons_l_ton" = 1130