出于某种原因,这只会返回正确的相应城市并计入国家/地区,但拒绝退回国家/地区列。第二列和第三列返回左移一。结果是正确的,就在我调用SELECT country.name时,这个字段没有返回。
SELECT
country.name,
city.name,
COUNT(country_language.language) AS count
FROM
lab6.country,
lab6.city,
lab6.country_language
GROUP BY
country.name,
country.country_code,
country_language.country_code,
city.name,
city.id
HAVING
COUNT(country_language.language) >= 8 AND
COUNT(country_language.language) <= 12 AND
country.country_code = country_language.country_code AND
country.capital = city.id
答案 0 :(得分:1)
您很可能需要为其中一个名称列添加别名,如下所示:
SELECT
country.name,
city.name as city_name,
COUNT(country_language.language) AS count
...