'大的国家'

11-homework-ligang/big_country.py

+#!/usr/bin/env python3
+#-*- coding:utf-8-*-
+"""
+这里有张 World 表
++-----------------+------------+------------+--------------+---------------+
+| name            | continent  | area       | population   | gdp           |+
+-----------------+------------+------------+--------------+---------------+|
+ Afghanistan     | Asia       | 652230     | 25500100     | 20343000      |
+ | Albania         | Europe     | 28748      | 2831741      | 12960000      |
+ | Algeria         | Africa     | 2381741    | 37100000     | 188681000     |
+ | Andorra         | Europe     | 468        | 78115        | 3712000       |
+ | Angola          | Africa     | 1246700    | 20609294     | 100990000     |
+ +-----------------+------------+------------+--------------+---------------+
+ 如果一个国家的面积超过300万平方公里，或者人口超过2500万，那么这个国家就是大国家。
+ 编写一个SQL查询，输出表中所有大国家的名称、人口和面积。例如，根据上表，我们应该输出
++--------------+-------------+--------------+
+| name         | population  | area         |
++--------------+-------------+--------------+
+| Afghanistan  | 25500100    | 652230       |
+| Algeria      | 37100000    | 2381741      |
++--------------+-------------+--------------+
+ 请写出SQL语句
+"""
+
+"""
+1、首先创建数据库 country
+    create database country default character set utf8 collate utf8_general_ci;
+2、创建数据表：
+
+    create table world(
+    id int(11) not null auto_increment.
+    name varchar(64)  not null,
+    continent varchar(20) not null,
+    area int(11) not null,
+    population int null,
+    gdp int(11)  null,
+    primary key(id)
+    )engine = InnoDB default charset =utf8;
+3、插入数据
+ insert into world(name,continent,area,population,gdp) values('Afghanistan','Asia',652230,25500100,20343000),
+ ('Albania','Europe',28748,2831741,12960000),(...)
+"""
+
+import pymysql
+#pymysql.install_as_MySQLdb()
+mydb = pymysql.Connect(
+    host='127.0.0.1',
+    port=3306,
+    user='root',
+    passwd='root',
+    db='country',
+    charset='utf8'
+)
+cursor = mydb.cursor()
+sql = " select name,population,area from world where area > 300000 or population > 25000000"
+cursor.execute(sql)
+rs = cursor.fetchmany()
+print(rs)
+cursor.close()
+mydb.close()
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