Mysql基本操作

• 创建数据库
  CREATE DATABASE database_name;
• 使用mysqladmin创建数据库
  mysqladmin -u root -p create database_name;
• Note: 使用普通用户需要特定的权限来创建数据库或着删除数据库

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• 删除数据库
  drop database database_name;
• 使用mysqladmin删除数据库
  mysqladmin -u root -p drop database_name;

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• 选中数据库
  use database_name;

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• 创建数据库表
  CREATE TABLE table_name (column_name column_type);

CREATE TABLE IF NOT EXISTS `user` (
    `id` INT UNSIGNED PRIMARY_KEY AUTO_INCREMENT,
    `desc` VARCHAR(255) NOT NULL,
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

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• 删除数据库表
  drop table table_name;

drop table user;

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• 插入数据
  INSERT INTO table_name (field1, field2, field3...) VALUES(value1, value2, value3...);

INSERT INTO user (username password)
VALUES('TONY', '123'),
('TOM', '1234');

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• 查询数据
  SELECT columns_name ... FROM table_name...

SELECT username FROM user;

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• where字句
  SELECT field1, ... FROM table_name, ... WHERE condition1 [AND [OR]] condition2....;

SELECT username FROM user where id = 1;

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• UPDATE字句
  UPDATE table_name SET field=new-value, filed1=new-value;

UPDATE user SET username='runserver';

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• DELETE语句
  DELETE FROM table_name [WHERE Clause];

DELETE FROM user WHERE username='runserver';

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• LIKE字句
  SELECT field1,... FROM table_name WHERE field LIKE condition [AND [OR]] field2 = 'do';

SELECT * FROM user WHERE username LIKE '%ver';

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• UNION操作符

SELECT field....
FROM tables
[WHERE conditions]
UNION [ALL | DISTINCT]
SELECT field....
FROM tables
[WHERE condition];

SELECT country FROM websites
UNION
SELECT country FROM apps
ORDER BY country;

SELECT country FROM websites
UNION ALL
SELECT country FROM apps
ORDER BY country;

SELECT country, name FROM websites
WHERE country='cn'
UNION ALL
SELECT country, app_name FROM apps
WHERE country = 'cn'
ORDER BY country;

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• 排序

SELECT field... FROM talbe1, table2...
ORDER BY field1, [field2...] [ASC [DESC]]

SELECT * FROM user ORDER BY id asc;

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• GROUP BY语句

SELECT column_name, function(column_name)
FROM table_name
WHERE column_name operator value
GROUP BY column_name;

SELECT name, COUNT(*) FROM user GROUP BY id;

SELECT name SUM(score) as score_number 
FROM user GROUP BY name WITH ROLLUP;

SELECT coalesce(name, 'total'), SUM(socre) as sum FROM user
GROUP BY name WITH ROLLUP;

Note：WITH ROLLUP可以实现在分组统计数据基础上在进行相同的统计
coalesce()可以设置一个取代null的名称

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今天先弄到这