1.
Select * From tablename
2.
INSERT INTO tablename
(longitude, latitude, housing_median_age, total_rooms, total_bedrooms, population, households, median_income, median_house_value)
VALUES('-200.000000', '20.000000', '20.000000', '20.000000', '20.000000', '20.000000', '20.000000', '2.000000', '200000.000000');
INSERT INTO tablename
(longitude, latitude, housing_median_age, total_rooms, total_bedrooms, population, households, median_income, median_house_value)
VALUES('-300.000000', '30.000000', '30.000000', '3000.000000', '300.000000', '300.000000', '300.000000', '3.000000', '300000.000000');
4.
Select * From tablename
Select * From tablename Where longitude = '-200.000000'
Select * From tablename Where longitude = '-300.000000'
Delete From tablename Where longitude = '-200.000000'
Delete From tablename Where longitude = '-300.000000'
Select * From tablename