mysql 表创建

CREATE TABLE table_name (
    column1 datatype,
    column2 datatype,
    ...
    columnN datatype,
    PRIMARY KEY (column1, column2, ...),
    FOREIGN KEY (column_name) REFERENCES other_table (column_name)
);

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) NOT NULL,
    email VARCHAR(100) NOT NULL UNIQUE,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- 检查表是否存在
SHOW TABLES LIKE 'users';

-- 如果表存在，删除表
DROP TABLE IF EXISTS users;

-- 重新创建表
CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) NOT NULL,
    email VARCHAR(100) NOT NULL UNIQUE,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);