【MySQL】（十三）浅谈 MySQL 索引优化分析2

//所表一起创建：
CREATE TABLE customer (
  id INT(10) UNSIGNED AUTO_INCREMENT ,
  customer_no VARCHAR(200),
  customer_name VARCHAR(200), 
  PRIMARY KEY(id), 
  KEY (customer_name)  // Σ(っ °Д °;)っ
);
//单独建单值索引：
CREATE INDEX idx_customer_name ON

//随表一起创建： 
CREATE TABLE customer (
  id INT(10) UNSIGNED AUTO_INCREMENT ,
  customer_no VARCHAR(200),
  customer_name VARCHAR(200), 
  PRIMARY KEY(id), 
  KEY (customer_name), 
  UNIQUE (customer_no)   // Σ(っ °Д °;)っ
);
//单独建唯一索引： 
CREATE UNIQUE INDEX idx_customer_no ON customer(customer_no);

//随表一起建索引
CREATE TABLE customer (
  id INT(10) UNSIGNED AUTO_INCREMENT ,
  customer_no VARCHAR(200),
  customer_name VARCHAR(200), 
  PRIMARY KEY(id)   // Σ(っ °Д °;)っ
);
//单独建主键索引：
ALTER TABLE customer add PRIMARY KEY customer(customer_no);
//删除建主键索引：
ALTER TABLE customer drop PRIMARY KEY ;
//修改建主键索引：
必须先删除掉(drop)原索引，再新建(add)索引

CREATE TABLE customer (
  id INT(10) UNSIGNED AUTO_INCREMENT ,
  customer_no VARCHAR(200),
  customer_name VARCHAR(200), 
  PRIMARY KEY(id), 
  KEY (customer_name), 
  UNIQUE (customer_name), 
  KEY (customer_no,customer_name)  // Σ(っ °Д °;)っ
);
单独建索引： 
CREATE INDEX idx_no_name ON customer(customer_no,customer_name);