sql select 基础用法
1 数据集介绍
在线运行：
https://sqlzoo.net/wiki/SELECT_basics
2 练习题
2.1 知识储备
- 字符串需要使用单引号
- 使用
in可以检查某一项是否位于某个列表内 - 使用
between XXX and XXX可以检查某一项是否位于某个范围内
2.2 练习
show the population of Germany
select population from world where name = 'Germany';
Show the name and the population for ‘Sweden’, ‘Norway’ and ‘Denmark’.
select name,population from world where name in ('Sweden','Norway','Denmark');
show the country and the area for countries with an area between 200,000 and 250,000
select name,area from world where area between 200000 and 250000;
3 十三道和world表关联的sql语句
https://sqlzoo.net/wiki/SELECT_from_WORLD_Tutorial
1
SELECT name, continent, population FROM world
2
select name from world where population > 200000000;
3
select name, gdp/population from world where population > 200000000;
4
select name,population/1000000 from world where continent = 'South America';
5
select name,population from world where name in ('France','Germany','Italy');
6
select name from world where name like '%United%';
7
select name,population,area from world where area > 3000000 or population > 250000000;
8
select name,population,area from world where area > 3000000 and population < 250000000 or area < 3000000 and population > 250000000;
9
select name,round(population/1000000,2),round(gdp/1000000000,2) from world where continent = 'South America';
10
select name,round(gdp/population,-3) from world where gdp > 1000000000000;
11
SELECT name,capital FROM world
WHERE LEN(name)=LEN(capital)12
select name,capital from world where left(name,1) = left (capital,1) and name <> capital;
13
select name from world where name like '%a%' and name like '%e%' and name like '%i%' and name like '%o%' and name like '%u%' and name not like '% %';
4 十四道和nobel表关联的sql语句
https://sqlzoo.net/wiki/SELECT_from_Nobel_Tutorial
1
select * from nobel where yr=1950;
2
SELECT winnerFROM nobelWHERE yr = 1962AND subject = 'literature'
3
select yr,subject from nobel where winner='Albert Einstein'
4
select winner from nobel where yr >= 2000 and subject = 'peace';
5
select * from nobel where yr between 1980 and 1989 and subject = 'literature'
6
select * from nobel where winner in ('Theodore Roosevelt','Woodrow Wilson','Jimmy Carter','Barack Obama');
7
select winner from nobel where winner like 'John%';
8
select yr,subject,winner from nobel where (yr=1980 and subject='physics') or (yr=1984 and subject='chemistry')
9
select yr,subject,winner from nobel where yr=1980 and subject not in ('chemistry');
10
select yr,subject,winner from nobel where (subject='Medicine' and yr < 1910) or (subject='Literature' and yr>=2004)
11
select * from nobel where winner = 'PETER GRÜNBERG'
12
select * from nobel where winner = 'EUGENE O''NEILL'
13
select winner,yr,subject from nobel where winner like 'Sir%' order by yr desc,winner asc;
14
应该是正确答案，但是不对，不知道为啥：
SELECT winner, subject FROM nobel
WHERE yr=1984
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