select a.*,c1.cityname as 出发城市,c2.cityname as 到达城市 from air a left join city c1 on c1.id = a.fromCityId left join city c2 on c2.id = a.toCityID

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SQL code

SELECT A.id, C1.cityName fromCityName, C2.cityName toCityName, A.price, A.dateTimes
FROM Air A
JOIN City C1
ON A.fromCityId=C1.id
JOIN City C2
ON A.toCityId=C2.id