mysql 获取表主键

SHOW CREATE TABLE table_name;

DESCRIBE table_name;

DESC table_name;

SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE TABLE_SCHEMA = 'database_name' AND TABLE_NAME = 'table_name' AND CONSTRAINT_NAME = 'PRIMARY';

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(50),
    email VARCHAR(50) UNIQUE
);

SHOW CREATE TABLE users;

CREATE TABLE `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(50) DEFAULT NULL,
  `email` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

DESCRIBE users;

+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(11)     | NO   | PRI | NULL    | auto_increment |
| name  | varchar(50) | YES  |     | NULL    |                |
| email | varchar(50) | YES  | UNI | NULL    |                |
+-------+-------------+------+-----+---------+----------------+

SELECT COUNT(*)
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE TABLE_SCHEMA = 'database_name' AND TABLE_NAME = 'table_name' AND CONSTRAINT_TYPE = 'PRIMARY KEY';