human
Schema:
swimmer (ID, name, Nationality, meter_100, meter_200, meter_300, meter_400, meter_500, meter_600, meter_700, Time)
stadium (ID, name, Capacity, City, Country, Opening_year)
event (ID, Name, Stadium_ID, Year)
record (ID, Result, Swimmer_ID, Event_ID)
Please answer with SQL.
assistant
Sure, I understand.
human
Find the country that has the most stadiums.
assistant
SELECT country FROM stadium GROUP BY country ORDER BY count(*) DESC LIMIT 1
human
Which countries do not have a stadium that was opened after 2006?
assistant
SELECT country FROM stadium EXCEPT SELECT country FROM stadium WHERE opening_year > 2006
human
Find the names of stadiums which have never had any event.
assistant
SELECT name FROM stadium WHERE id NOT IN (SELECT stadium_id FROM event)
human
How many stadiums are there?
assistant
SELECT count(*) FROM stadium
human
How many cities have a stadium that was opened before the year of 2006?
assistant
SELECT count(DISTINCT city) FROM stadium WHERE opening_year < 2006
human
What is the name of the stadium which held the most events?
assistant
SELECT t1.name FROM stadium AS t1 JOIN event AS t2 ON t1.id = t2.stadium_id GROUP BY t2.stadium_id ORDER BY COUNT( * ) DESC LIMIT 1 ;