SQLZOOL练习题
网址
https://sqlzoo.net/wiki/SQL_Tutorial
目录

–第0关 https://sqlzoo.net/wiki/SELECT_basics，
– 练习where = in between


-- Modify it to show the population of Germany
-- 练习 where = 单个筛选 ，字符串要用单引号''

select population 
from world
where name = 'Germany'


--Show the name and the population for 'Sweden', 'Norway' and 'Denmark'.
-- 练习 where in 多个筛选
select name, population
from world 
where name in ('Denmark', 'Norway', 'Sweden')

/*就算你写出where name in ('Sweden','Norway','Denmark'), sql也会默认字母或数字升序。*/
-- 练习where between 区域筛选。 

select name, area
from world
where area between 200000 and 250000