考虑以下表格架构：// Sets the image for the EU volume limit. When appropriate, this image will be displayed on top of the
// maximumVolumeSliderImage. It must be visually distinct from the maximumVolumeSliderImage, and use
// a color similar to the default, to convey a sense of warning to the user. The same image is used for
// all control states. For debugging purposes, switch on the "EU Volume Limit" setting in the Developer
// menu of the Settings application to always enable the volume limit.
@property (nonatomic, strong, nullable) UIImage *volumeWarningSliderImage NS_AVAILABLE_IOS(7_0);
。假设这些公司可能位于几个城市。找到所有公司
位于'公司X'所在的每个城市。
这是正确的SQL代码：
company(company-name, city 这是否与：
相同 select company name from company
where city in (select city from company where company-name = 'Company X')
答案 0 :(得分：0)
使用联接
可能更好SELECT DISTINCT c1.company_name
FROM company AS c1
JOIN company AS c2 ON c1.city = c2.city
WHERE c2.company_name = 'Company X'
答案 1 :(得分：-1)
如果您的字段被调用＆＃34;公司名称＆＃34;查询应该是
select "company-name"
from company
where city in (select city from company where "company-name" = 'Company X')
如果该公司的名称知道它的独特之处，您可以替换＆＃34; in＆＃34;运算符＆＃34; =＆＃34;