mysql中sql语句

CREATE TABLE `user` (
  id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
  name varchar(100) COMMENT '名字',
  age int COMMENT '年龄',
  address varchar(255) COMMENT '地址',
  create_time timestamp DEFAULT CURRENT_TIMESTAMP  COMMENT '创建时间'
) COMMENT '用户表'

create table 表名字 (
  id字段名称 int数据类型代表数字类型 NOT NULL(不能为空) AUTO_INCREMENT(id自增)
  PRIMARY KEY(id为主键)
  name(字段名称) varchar(100)字符串类型100字符 COMMENT(注释)
  age(字段名称) int数据类型代表数字类型 COMMENT(注释)
  create_time(字段名称) timestamp(时间戳) DEFAULT CURRENT_TIMESTAMP(自动填充创建时间)
)


create database 库名
create database if not exists 库名

default character set = 'utf8mb4'

ALTER TABLE 'user' RENAME `user2` // 改表名
ALTER TABLE 'user' Add COLUMN 'hobby' VARCHAR(200) // 添加字段/列
ALTER TABLE 'user' DROP COLUMN 'hobby' // 删除字段/列
ALTER TABLE 'user' MODIFY COLUMN 'age' VARCHAR(255) NULL COMMENT '年龄2' // 修改字段/列属性

SELECT 'name' FROM 'user'
SELECT 'name','id' FROM 'user'
SELECT * FROM 'user'
SELECT 'name' as 'user_name','id' as 'user_id' FROM 'user' // 列的别名 as
SELECT * FROM 'user' ORDER BY id DESC // ORDER BY [字段名称] desc降序(从大到小) asc 升序(从小到大)
SELECT * FROM 'user' LIMIT 1,3  // limit [开始行] [限制条数]
SELECT * FROM 'user' WHERE name = "name" // 条件查询
SELECT * FROM 'user' WHERE name = '小王' AND age <= 20
SELECT * FROM 'user' WHERE name = '小王' OR age <= 22;
SELECT * FROM 'user' WHERE name LIKE '%张%'

INSERT INTO user('name','hobby','age') VALUES('xiao','basketball',18) // 新增
INSERT INTO user('name','hobby','age') VALUES(NULL,NULL,NULL) 
INSERT INTO user('name','hobby','age') VALUES(NULL,NULL,NULL),('xiaoman','basketball',18)

DELETE FROM `user` WHERE id = 11 // 删除
DELETE FROM `user` WHERE id IN (8,9,10)

UPDATE 'user' SET name='李四',age=30,hobby='篮球' WHERE id = 12  // 更新