如何在WHERE中使用多个子查询

Question

刚开始学习SQL，经过一百万次谷歌搜索，我无法找到答案。

SELECT name, population FROM world
WHERE population > (SELECT population FROM world 
WHERE name = 'Canada');
WHERE population < (SELECT population FROM world
WHERE name = 'Poland');

我知道你可以使用＆＃34;加入＆＃34;或类似的东西但使用子查询我该怎么做？基本上，我寻找的人口比加拿大人大，但比波兰人少。

Answer 1

你几乎拥有它。只需要一个AND而不是分号。

SELECT name, population FROM world
WHERE population > (SELECT population FROM world WHERE name = 'Canada')
AND
WHERE population < (SELECT population FROM world WHERE name = 'Poland');

：）

Answer 2

SELECT name, population FROM world
WHERE population > (SELECT population FROM world 
WHERE name = 'Canada') AND 
population < (SELECT population FROM world
WHERE name = 'Poland');

Answer 3

尝试使用AND。

SELECT name, population FROM world
WHERE population > (SELECT population FROM world WHERE name = 'Canada')
AND population < (SELECT population FROM world WHERE name = 'Poland');

Answer 4

阅读基本语法。

尝试

SELECT name, population FROM world WHERE population > (SELECT population FROM world WHERE name = 'Canada'); AND population < (SELECT population FROM world WHERE name = 'Poland');