mysql8常用命令

Posted 2020-12-09 ssh_alitheia

目录

• 连接
• 导入数据
• 查询
• 插入
• 更新
• 删除
• 创建和操纵表
• 视图
• 存储过程
• 游标
• 触发器
• 事务
• 字符集
• 安全

连接

-- 不要在命令行中输入密码
mysql -h localhost -P 3306 -u <username> -p
Enter Password :
-- 指定数据库
mysql u root -p company

CREATE DATABASE company;
CREATE DATABASE `my.contacts`;
USE company;
-- 要查找连接到了哪个数据库
SELECT DATABASE();
SHOW DATABASES;
SHOW TABLES;
-- 表结构
SHOW CREATE TABLE customers;
DESC customers;
-- 当前的数据目录
SHOW VARIABLES LIKE ‘datadir‘;

导入数据

-- 另存为文件
SELECT first_name, last_name INTO OUTFILE ‘result.csv‘;
-- 将数据加载到表中
LOAD DATA INFILE ‘result.csv‘ INTO TABLE
employee_names
FIELDS TERMINATED BY ‘,‘
OPTIONALLY ENCLOSED BY ‘"‘
LINES TERMINATED BY ‘
‘;
-- 忽略1行
LOAD DATA INFILE ‘result.csv‘ INTO TABLE
employee_names
FIELDS TERMINATED BY ‘,‘
OPTIONALLY ENCLOSED BY ‘"‘
LINES TERMINATED BY ‘
‘
IGNORE 1 LINES;

LOAD DATA INFILE ‘result.csv‘ REPLACE
INTO TABLE employee_names FIELDS TERMINATED BY ‘,‘OPTIONALLY ENCLOSED BY ‘"‘ LINES TERMINATED
BY ‘
‘;

LOAD DATA INFILE ‘result.csv‘ IGNORE INTO
TABLE employee_names FIELDS TERMINATED BY
‘,‘OPTIONALLY ENCLOSED BY ‘"‘ LINES TERMINATED
BY ‘
‘;

查询

-- 查询
SELECT * FROM departments;
SELECT emp_no, dept_no FROM dept_manager;
SELECT COUNT(*) FROM employees;
SELECT emp_no FROM employees WHERE first_name=‘Georgi‘ AND last_name=‘Facello‘;
-- in
SELECT COUNT(*) FROM employees WHERE last_name IN (‘Christ‘, ‘Lamba‘, ‘Baba‘);
-- BETWEEN
SELECT COUNT(*) FROM employees WHERE hire_date BETWEEN ‘1986-12-01‘ AND ‘1986-12-31‘;
SELECT COUNT(*) FROM employees WHERE hire_date NOT BETWEEN ‘1986-12-01‘ AND ‘1986-12-31‘;
-- 模式匹配
SELECT COUNT(*) FROM employees WHERE first_name LIKE ‘christ%‘;
-- 匹配单个字符
SELECT prod_id, prod_name FROM products WHERE prod_name LIKE ‘_ ton anvil‘;
-- 正则
SELECT COUNT(*) FROM employees WHERE first_name RLIKE ‘^christ‘;
SELECT COUNT(*) FROM employees WHERE last_name REGEXP ‘ba$‘;
-- 别名 AS
SELECT COUNT(*) AS count FROM employees WHERE hire_date BETWEEN ‘1986-12-01‘ AND ‘1986-12-31‘;

-- 排序 限制结果数量
SELECT emp_no,salary FROM salaries ORDER BY salary DESC LIMIT 5;
-- 按多个列排序
SELECT prod_id, prod_price, prod_name FROM products ORDER BY prod_price, prod_name;
-- 排序方向
SELECT prod_id, prod_price, prod_name FROM products ORDER BY prod_price DESC;

-- 分组
SELECT gender, COUNT(*) AS count FROM employees GROUP BY gender;
-- 去重
SELECT DISTINCT title FROM titles;
-- HAVING 子句来过滤GROUP BY 子句的结果
SELECT emp_no, AVG(salary) AS avg FROM salaries GROUP BY emp_no HAVING avg > 140000 ORDER BY avg DESC;

-- join
SELECT vend_name, prod_name, prod_price
FROM vendors, products
WHERE vendors.vend_id = products.vend_id
ORDER BY vend_name, prod_name;

-- join 和上面一样，为等值联结，不过明确指出join，推荐
SELECT vend_name, prod_name, prod_price
FROM vendors INNER JOIN products
ON vendors.vend_id = products.vend_id;

插入

-- 插入完整的行
INSERT INTO Customers VALUES(NULL, ‘Pep E. LaPew‘, ‘100 Main Street‘);
-- 指明列，可以插入部分，不依赖顺序
INSERT INTO customers(cust_name, cust_address) VALUES(‘Pep E. LaPew‘, ‘100 Main Street‘);
-- 插入多行
INSERT INTO customers(cust_name, cust_address) VALUES(‘Pep E. LaPew‘, ‘100 Main Street‘),(‘Pep E. LaPew‘, ‘100 Main Street‘);
-- 插入检索出的数据
INSERT INTO customers(cust_id, cust_contact) SELECT cust_id, cust_contact FROM custnew;

INSERT IGNORE INTO `company`.`customers`(first_name, last_name,country) VALUES (‘Mike‘, ‘Christensen‘, ‘USA‘);

更新

UPDATE customers SET cust_email = ‘[e-mail]‘ WHERE cust_id = 10005;
-- 多个列
UPDATE customers SET cust_name = ‘The Fudds‘, cust_email = ‘[e-mail]‘ WHERE cust_id = 10005;
UPDATE customers SET first_name=‘Rajiv‘,country=‘UK‘ WHERE id=4;

删除

DELETE FROM customers WHERE cust_id = 10006;
-- 删除所有内容，高危
DELETE FROM customers;
-- 快速清空表内容
TRUNCATE TABLE customers;

创建和操纵表

CREATE TABLE customers
(
  cust_id int NOT NULL AUTO_INCREMENT,
  cust_name char(50) NOT NULL ,
  cust_address char(50) NULL ,
  cust_city char(50) NULL ,
  cust_state char(5) NULL ,
  cust_zip char(10) NULL DEFAULT ‘123‘,
  cust_country char(50) NULL ,
  cust_contact char(50) NULL ,
  cust_email char(255) NULL ,
  PRIMARY KEY (cust_id)
) ENGINE=InnoDB;

-- 修改表结构
ALTER TABLE vendors ADD vend_phone CHAR(20);
ALTER TABLE Vendors DROP COLUMN vend_phone;
-- 定义外键
ALTER TABLE orderitems ADD CONSTRAINT fk_orderitems_orders FOREIGN KEY (order_num) REFERENCES orders (order_num);

-- 删除表
DROP TABLE customers2;
-- 重命名表
RENAME TABLE customers2 TO customers;

-- 克隆表结构
CREATE TABLE new_customers LIKE customers;

视图

-- 创建视图
CREATE VIEW productcustomers AS
SELECT cust_name, cust_contact, prod_id
FROM customers, orders, orderitems
WHERE customers.cust_id = orders.cust_id
AND orderitems.order_num = orders.order_num;

-- 使用视图
SELECT cust_name, cust_contact
FROM productcustomers
WHERE prod_id = ‘TNT2‘;

存储过程

-- 执行存储过程
CALL productpricing(@pricelow, @pricehigh, @priceaverage);
-- 创建存储过程
CREATE PROCEDURE productpricing()
BEGIN
SELECT Avg(prod_price) AS priceaverage
FROM products;
END;
-- 删除存储过程
CALL productpricing();

-- 使用参数
CREATE PROCEDURE productpricing(
OUT pl DECIMAL(8,2),
OUT ph DECIMAL(8,2),
OUT pa DECIMAL(8,2)
) BEGIN
SELECT Min(prod_price)
INTO pl
FROM products;
SELECT Max(prod_price)
INTO ph
FROM products;
SELECT Avg(prod_price)
INTO pa
FROM products;
END;
-- 调用
CALL productpricing(@pricelow,
@pricehigh,
@priceaverage);
-- 
SELECT @priceaverage;

-- 检查存储过程
SHOW CREATE PROCEDURE ordertotal;

游标

-- 创建游标 DECLAR 定义了名为ordernumbers的游标
CREATE PROCEDURE processorders()
BEGIN
DECLARE ordernumbers CURSOR
FOR
SELECT ordernum FROM orders;
END;

OPEN ordernumbers;
CLOSE ordernumbers;

CREATE PROCEDURE processorders()
BEGIN
-- Declare the cursor
DECLARE ordernumbers CURSOR
FOR
SELECT order_num FROM orders;
-- Open the cursor
OPEN ordernumbers;
-- Close the cursor
CLOSE ordernumbers;
END;

触发器

-- 创建触发器
CREATE TRIGGER newproduct AFTER INSERT ON products
FOR EACH ROW SELECT ‘Product added‘;
-- 删除触发器
DROP TRIGGER newproduct;

事务

-- 事务的开始
START TRANSACTION
-- ROLLBACK
SELECT * FROM ordertotals;
START TRANSACTION;
DELETE FROM ordertotals;
SELECT * FROM ordertotals;
ROLLBACK;
SELECT * FROM ordertotals;

-- 使用COMMIT
START TRANSACTION;
DELETE FROM orderitems WHERE order_num = 20010;
DELETE FROM orders WHERE order_num = 20010;
COMMIT;

-- 保留点
SAVEPOINT delete1;
ROLLBACK TO delete1;

字符集

-- 查看所支持的字符集完整列表
SHOW CHARACTER SET;
-- 查看所支持校对的完整列表
SHOW COLLATION;
-- 确定所用的字符集和校对
SHOW VARIABLES LIKE ‘character%‘;
SHOW VARIABLES LIKE ‘collation%‘;

-- 给表指定字符集和校对
CREATE TABLE mytable
(
columnn1 INT,
columnn2 VARCHAR(10)
) DEFAULT CHARACTER SET hebrew
COLLATE hebrew_general_ci;

-- 对每个列设置
CREATE TABLE mytable
(
columnn1 INT,
columnn2 VARCHAR(10),
column3 VARCHAR(10) CHARACTER SET latin1 COLLATE latin1_general_ci
) DEFAULT CHARACTER SET hebrew
COLLATE hebrew_general_ci;

-- 在SELECT语句自身中进行
SELECT * FROM customers
ORDER BY lastname, firstname COLLATE latin1_general_cs;

安全

-- 创建用户
CREATE USER IF NOT EXISTS ‘company_read_only‘@‘localhost‘ IDENTIFIED WITH mysql_native_password
BY ‘company_pass‘
WITH MAX_QUERIES_PER_HOUR 500
MAX_UPDATES_PER_HOUR 100;

CREATE USER ben IDENTIFIED BY ‘p@$$w0rd‘;

-- 使用hash值
CREATE USER IF NOT EXISTS
‘company_read_only‘@‘localhost‘
IDENTIFIED WITH mysql_native_password
AS ‘*EBD9E3BFD1489CA1EB0D2B4F29F6665F321E8C18‘
WITH MAX_QUERIES_PER_HOUR 500
MAX_UPDATES_PER_HOUR 100;

-- 重新命名
RENAME USER ben TO bforta;
-- 删除用户账号
DROP USER bforta;

-- 授予和撤销用户的访问权限
GRANT SELECT ON company.* TO ‘company_read_only‘@‘localhost‘;
-- 限制查询列
GRANT SELECT(first_name,last_name) ON employees.employees TO ‘employees_ro‘@‘%‘
GRANT ALL ON *.* TO ‘dbadmin‘@‘%‘;

-- 检查权限
SHOW GRANTS FOR ‘employees_ro‘@‘%‘;
-- 撤销 FROM
REVOKE DELETE ON company.* FROM ‘company_write‘@‘%‘;
-- user表 没事别改它
SELECT * FROM mysql.user WHERE user=‘dbadmin‘G
UPDATE mysql.user SET host=‘localhost‘ WHERE user=‘dbadmin‘;
FLUSH PRIVILEGES;

-- 密码有效期
-- 创建一个具有过期密码的用户
CREATE USER ‘developer‘@‘%‘ IDENTIFIED WITH mysql_native_password AS
‘*EBD9E3BFD1489CA1EB0D2B4F29F6665F321E8C18‘ PASSWORD EXPIRE;
-- 改密
ALTER USER ‘developer‘@‘%‘ IDENTIFIED WITH 
mysql_native_password BY ‘new_company_pass‘;
-- 手动设置过期用户
ALTER USER ‘developer‘@‘%‘ PASSWORD EXPIRE;
-- 要求用户每隔90 天更改一次密码
ALTER USER ‘developer‘@‘%‘ PASSWORD EXPIRE INTERVAL 90 DAY;
-- 锁定账户
ALTER USER ‘developer‘@‘%‘ ACCOUNT LOCK;
ALTER USER ‘developer‘@‘%‘ ACCOUNT UNLOCK;


-- 角色
CREATE ROLE ‘app_read_only‘, ‘app_writes‘, ‘app_developer‘;
GRANT SELECT ON employees.* TO ‘app_read_only‘;
GRANT INSERT, UPDATE, DELETE ON employees.* TO ‘app_writes‘;
GRANT ALL ON employees.* TO ‘app_developer‘;
GRANT ‘app_read_only‘, ‘app_writes‘ TO ‘emp_read_write‘@‘%‘;