CREATE TABLE screen_mode (graphics_mode DECIMAL, char_cells TEXT, pixels TEXT, hardware_colours DECIMAL, used_kb DECIMAL, map TEXT, type TEXT)
CREATE TABLE phone (company_name TEXT, hardware_model_name TEXT, accreditation_type TEXT, accreditation_level TEXT, date TEXT, chip_model TEXT, screen_mode TEXT)
CREATE TABLE chip_model (model_name TEXT, launch_year DECIMAL, ram_mib DECIMAL, rom_mib DECIMAL, slots TEXT, wifi TEXT, bluetooth TEXT)

List the maximum, minimum and average number of used kb in screen mode.
SELECT MAX(used_kb), MIN(used_kb), AVG(used_kb) FROM screen_mode
SELECT MAX("used_kb"), MIN("used_kb"), AVG("used_kb") FROM "screen_mode"