帮我加个索引优化一下 CREATE TABLE person_info( id INT NOT NULL auto_increment, name VARCHAR(100) NOT NULL, birthday DATE NOT NULL, phone_number CHAR(11) NOT NULL, country varchar(100) NOT NULL, PRIMARY KEY (id), );
时间: 2023-11-28 12:03:38 浏览: 46
可以考虑在查询语句中经常用到的字段上创建索引,以下是一个可能的索引优化方案:
```
CREATE TABLE person_info (
id INT NOT NULL AUTO_INCREMENT,
name VARCHAR(100) NOT NULL,
birthday DATE NOT NULL,
phone_number CHAR(11) NOT NULL,
country VARCHAR(100) NOT NULL,
PRIMARY KEY (id),
INDEX idx_name (name),
INDEX idx_birthday (birthday),
INDEX idx_phone_number (phone_number),
INDEX idx_country (country)
);
```
这里我们在 `name`、`birthday`、`phone_number` 和 `country` 字段上创建了索引。
需要注意的是,对于数据量比较大的表,创建索引可能会影响写入性能,因此需要权衡索引的数量和查询性能之间的关系。在实际使用中,可以根据查询语句的性能来进行优化。
相关问题
create table cate( id primary key auto_increment int not null, cate varchar(11) not null ) 这一段错在哪
在创建表的语句中,有两个问题导致语法错误:
1. 缺少逗号:在每个字段属性后面需要添加逗号,用于分隔不同的字段。在第一行的字段属性 "id" 后面缺少逗号。
2. 错误的主键定义:在 "id" 字段的属性中,主键的定义应该放在数据类型之后,并且用括号括起来。正确的主键定义应为 "id int not null primary key auto_increment"。
修正后的语句如下:
```sql
CREATE TABLE cate(
id int not null primary key auto_increment,
cate varchar(11) not null
);
```
注意,修正后的语句只解决了语法错误,实际使用时还需要考虑是否符合业务需求和数据库设计规范。
CREATE TABLE customer ( id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(50) NOT NULL, gender ENUM('男', '女') NOT NULL, phone VARCHAR(20) NOT NULL, address VARCHAR(100) NOT NULL ); CREATE TABLE car_model( id INT PRIMARY KEY AUTO_INCREMENT, brand VARCHAR(50) NOT NULL, model VARCHAR(50) NOT NULL, price DECIMAL(10,2) NOT NULL ); CREATE TABLE car( model_id INT PRIMARY KEY AUTO_INCREMENT, color VARCHAR(50) NOT NULL, description VARCHAR(50) NOT NULL ); CREATE TABLE order1( id INT PRIMARY KEY AUTO_INCREMENT, customer_id INT NOT NULL, car_id INT NOT NULL, order_date DATETIME NOT NULL , price DECIMAL(10,2) NOT NULL, ); CREATE TABLE employee( id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(50) NOT NULL, gender ENUM('男', '女') NOT NULL, phone VARCHAR(20) NOT NULL, address VARCHAR(100) NOT NULL, salary DECIMAL(10,2) NOT NULL给出五个存储函数以及调用语句 );
存储函数1:
DELIMITER //
CREATE FUNCTION get_total_price(order_id INT)
RETURNS DECIMAL(10,2)
BEGIN
DECLARE total_price DECIMAL(10,2);
SELECT SUM(price) INTO total_price FROM order1 WHERE id = order_id;
RETURN total_price;
END//
DELIMITER ;
调用语句:SELECT get_total_price(1);
存储函数2:
DELIMITER //
CREATE FUNCTION get_customer_orders(customer_name VARCHAR(50))
RETURNS INT
BEGIN
DECLARE order_count INT;
SELECT COUNT(*) INTO order_count FROM order1 o JOIN customer c ON o.customer_id = c.id WHERE c.name = customer_name;
RETURN order_count;
END//
DELIMITER ;
调用语句:SELECT get_customer_orders('John Doe');
存储函数3:
DELIMITER //
CREATE FUNCTION get_employee_salary_increase(employee_id INT, percent DECIMAL(10,2))
RETURNS DECIMAL(10,2)
BEGIN
UPDATE employee SET salary = salary * (1 + percent/100) WHERE id = employee_id;
RETURN salary;
END//
DELIMITER ;
调用语句:SELECT get_employee_salary_increase(1, 10);
存储函数4:
DELIMITER //
CREATE FUNCTION get_model_count(brand_name VARCHAR(50))
RETURNS INT
BEGIN
DECLARE model_count INT;
SELECT COUNT(*) INTO model_count FROM car_model WHERE brand = brand_name;
RETURN model_count;
END//
DELIMITER ;
调用语句:SELECT get_model_count('Toyota');
存储函数5:
DELIMITER //
CREATE FUNCTION get_car_info(car_id INT)
RETURNS VARCHAR(100)
BEGIN
DECLARE car_info VARCHAR(100);
SELECT CONCAT(c.color, ' ', cm.brand, ' ', cm.model) INTO car_info FROM car c JOIN car_model cm ON c.model_id = cm.id WHERE c.id = car_id;
RETURN car_info;
END//
DELIMITER ;
调用语句:SELECT get_car_info(1);