mysql命令show columns

SHOW COLUMNS FROM table_name;

SHOW COLUMNS FROM database_name.table_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
);

SHOW COLUMNS FROM users;

+----------+-------------+------+-----+---------+----------------+-------+
| Field    | Type        | Null | Key | Default | Extra          | Privileges |
+----------+-------------+------+-----+---------+----------------+-------+
| id       | int(11)     | NO   | PRI | NULL    | auto_increment | SELECT,INSERT,UPDATE,REFERENCES |
| username | varchar(50) | NO   |     | NULL    |                | SELECT,INSERT,UPDATE,REFERENCES |
| email    | varchar(100)| NO   | UNI | NULL    |                | SELECT,INSERT,UPDATE,REFERENCES |
| created_at | timestamp   | NO   |     | CURRENT_TIMESTAMP |                | SELECT,INSERT,UPDATE,REFERENCES |
+----------+-------------+------+-----+---------+----------------+-------+