自学SQL语言的例子（使用MySQL实现）

/*
Date:2016/2/14
Description:SQL Learning-1
Writer:Wayne
*/
CREATE DATABASE game_db;    #创建一个数据库
USE game_db;                #指定当前使用数据库
CREATE TABLE game            #创建数据表
(
    id                INT PRIMARY KEY AUTO_INCREMENT,
    job_name        VARCHAR(20),
    weapons            VARCHAR(20),
    skills            VARCHAR(20),
    hero_type        VARCHAR(20)
);
#往数据表中添加数据
INSERT INTO game VALUES(1, ‘英雄‘, ‘剑、斧、钝器‘, ‘终极打击‘, ‘warrior‘),
                       (2, ‘圣骑士‘, ‘剑、钝器‘, ‘神圣冲击‘, ‘warrior‘),
                       (3, ‘黑骑士‘, ‘长枪、矛‘, ‘黑暗穿刺‘, ‘warrior‘),
                       (4, ‘主教‘, ‘长杖、短仗‘, ‘圣光普照‘, ‘magician‘),
                       (5, ‘火毒法师‘, ‘长杖、短仗‘, ‘末日火焰‘, ‘magician‘),
                       (6, ‘冰雷法师‘, ‘长杖、短仗‘, ‘冰咆哮‘, ‘magician‘),
                       (7, ‘神射手‘, ‘弓‘, ‘暴风箭雨‘, ‘archer‘),
                       (8, ‘箭神‘, ‘弩‘, ‘终极扫射‘, ‘archer‘),
                       (9, ‘侠盗‘, ‘短剑、短刀‘, ‘暗杀‘, ‘ranger‘),
                       (10, ‘隐士‘, ‘拳套‘, ‘四连镖‘, ‘ranger‘),
                       (11, ‘暗影双刀‘, ‘短剑、短刀‘, ‘终极斩‘, ‘ranger‘);
SELECT * FROM game;                                                                        #查询指定表中全部数据
CREATE OR REPLACE VIEW warrior_view AS SELECT * FROM game WHERE hero_type=‘warrior‘;    #建立视图
SELECT *FROM warrior_view;                                                                #查询视图中数据
SELECT COUNT(*) FROM game;                                                                #统计视图中数据
SELECT hero_type AS Hero, COUNT(*) AS Num FROM game GROUP BY hero_type;                    #按指定段名分组查询数据
DROP TABLE game;                                                                        #删除指定表
DROP DATABASE game_db;                                                                    #删除指定数据库