mysql - 帮助子查询!返回多于 1 行

Question

我不明白返回多行的问题:

这是我的 table BBC:

name    region  area    population  gdp
Afghanistan South Asia  652225  26000000    
Albania Europe  28728   3200000 6656000000
Algeria Middle East 2400000 32900000    75012000000
Andorra Europe  468 64000   
Angola  Africa  1250000 14500000    14935000000
etc.............................

问题:

List the name and region of countries in the regions containing 'India', 'Iran'.

这是我的声明:

select name from bbc where region = (select region from bbc where name='India' or name='Iran')

它返回:

sql: errorSubquery returns more than 1 row

我的说法有什么问题吗？答案应该采用选择语句中的选择语句的形式

谢谢!

Answer 1

这是因为您正在尝试将 region 与值表进行比较。相反，请尝试使用 in:

select name 
from bbc 
where region in 
    (select region from bbc where name='India' or name='Iran')