CREATE TABLE event (ID INT, Name TEXT, Stadium_ID INT, Year TEXT)
CREATE TABLE swimmer (ID INT, name TEXT, Nationality TEXT, meter_100 FLOAT, meter_200 TEXT, meter_300 TEXT, meter_400 TEXT, meter_500 TEXT, meter_600 TEXT, meter_700 TEXT, Time TEXT)
CREATE TABLE stadium (ID INT, name TEXT, Capacity INT, City TEXT, Country TEXT, Opening_year INT)
CREATE TABLE record (ID INT, Result TEXT, Swimmer_ID INT, Event_ID INT)

Find Nationality and the amount of Nationality , and group by attribute Nationality, and visualize them by a bar chart, and show by the how many nationality from low to high.
SELECT Nationality, COUNT(Nationality) FROM swimmer GROUP BY Nationality ORDER BY COUNT(Nationality)
SELECT "Nationality", COUNT("Nationality") FROM "swimmer" GROUP BY "Nationality" ORDER BY COUNT("Nationality") NULLS FIRST