mysql desc(DESCRIBE)命令实例讲解

mysql desc命令用于查看表结构，是DESCRIBE命令的简写形式。

mysql desc命令语法：

desc tablename

该命令会显示表哪些信息呢？具体包括：

1. 字段名称(Field)
2. 字段类型(Type)
3. 字段是否为null
4. 字段是否为主键(key)
5. 字段的默认值(default)
6. Extra

实例：

mysql> CREATE TABLE employee (
    ->     ID INT(2) auto_increment primary key,
    ->     First_name VARCHAR(20),
    ->     Last_name VARCHAR(30),
    ->     Start_date DATE,
    ->     Salary int(6),
    ->     city VARCHAR(20),
    ->     de ion VARCHAR(20)
    -> );
Query OK, 0 rows affected (0.02 sec)

mysql>
mysql> desc employee;
+-------------+-------------+------+-----+---------+----------------+
| Field       | Type        | Null | Key | Default | Extra          |
+-------------+-------------+------+-----+---------+----------------+
| ID          | int(2)      | NO   | PRI | NULL    | auto_increment |
| First_name  | varchar(20) | YES  |     | NULL    |                |
| Last_name   | varchar(30) | YES  |     | NULL    |                |
| Start_date  | date        | YES  |     | NULL    |                |
| Salary      | int(6)      | YES  |     | NULL    |                |
| city        | varchar(20) | YES  |     | NULL    |                |
| de ion | varchar(20) | YES  |     | NULL    |                |
+-------------+-------------+------+-----+---------+----------------+
7 rows in set (0.00 sec)