用于获取给定值的唯一值的SQL查询

Question

我有一个表名CITY，这两列有'CITY_ID'和'PLACES'

我正在尝试获得CITY_ID，它应该只有这四个地方德州，阿拉巴马州，亚利桑那州，科罗拉多州，它不应该有任何其他地方。

select city_id from city 
where places in ('texas','alabama','arizona','colorado')
having count(city_id)=4
group by city_id

结果：我收到了很多包含这四个地方和其他地方的city_id。

请帮助

Answer 1

尝试执行以下操作

SELECT C._city_id FROM
  (SELECT city_id, places, count(places) as numplaces FROM Cities group by city_id) as C
WHERE C.places in ('texas', 'alabama','arizona','colorado') AND C.numplaces = 4

请注意，我的示例是在MySQL中完成的，如果需要，您必须调整SQL。

Answer 2

从城市中选择不同的city_id （'texas'，'alabama'，'arizona'，'colorado'）的地方;

应该有用。