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MySQL 显示列有几种方法

2022 年 08 月 24 日 • 阅读: 343 • 编码,MySQL

今天在写一个数据库查询的时候意外发现 describe 是一个 MySQL 关键字,而他的别名是 DESC 相比前者来说,后者的使用率更高一些.

后来翻了一下官方文档,发现显示列原来有这么多语句,不知道是否出于兼容其他数据库的原因。

mysql> SHOW COLUMNS FROM city;
+-------------+----------------------+------+-----+-------------------+-----------------------------+
| Field       | Type                 | Null | Key | Default           | Extra                       |
+-------------+----------------------+------+-----+-------------------+-----------------------------+
| city_id     | smallint(5) unsigned | NO   | PRI | NULL              | auto_increment              |
| city        | varchar(50)          | NO   |     | NULL              |                             |
| country_id  | smallint(5) unsigned | NO   | MUL | NULL              |                             |
| last_update | timestamp            | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-------------+----------------------+------+-----+-------------------+-----------------------------+
4 rows in set (0.02 sec)

mysql> EXPLAIN city;
+-------------+----------------------+------+-----+-------------------+-----------------------------+
| Field       | Type                 | Null | Key | Default           | Extra                       |
+-------------+----------------------+------+-----+-------------------+-----------------------------+
| city_id     | smallint(5) unsigned | NO   | PRI | NULL              | auto_increment              |
| city        | varchar(50)          | NO   |     | NULL              |                             |
| country_id  | smallint(5) unsigned | NO   | MUL | NULL              |                             |
| last_update | timestamp            | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-------------+----------------------+------+-----+-------------------+-----------------------------+
4 rows in set (0.02 sec)

mysql> DESC city;
+-------------+----------------------+------+-----+-------------------+-----------------------------+
| Field       | Type                 | Null | Key | Default           | Extra                       |
+-------------+----------------------+------+-----+-------------------+-----------------------------+
| city_id     | smallint(5) unsigned | NO   | PRI | NULL              | auto_increment              |
| city        | varchar(50)          | NO   |     | NULL              |                             |
| country_id  | smallint(5) unsigned | NO   | MUL | NULL              |                             |
| last_update | timestamp            | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-------------+----------------------+------+-----+-------------------+-----------------------------+
4 rows in set (0.03 sec)

mysql> DESCRIBE city;
+-------------+----------------------+------+-----+-------------------+-----------------------------+
| Field       | Type                 | Null | Key | Default           | Extra                       |
+-------------+----------------------+------+-----+-------------------+-----------------------------+
| city_id     | smallint(5) unsigned | NO   | PRI | NULL              | auto_increment              |
| city        | varchar(50)          | NO   |     | NULL              |                             |
| country_id  | smallint(5) unsigned | NO   | MUL | NULL              |                             |
| last_update | timestamp            | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-------------+----------------------+------+-----+-------------------+-----------------------------+
4 rows in set (0.03 sec)
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已有 2 条评论
  1. 2081386894@qq.com 2081386894@qq.com

    博主,你这个sql格式是什么软件的

    1. @2081386894@qq.com博客上展示的话,是通过 highlightjs 插件高亮展示的。
      链接数据库的客户端的话,通常使用 命令行工具链接,因为这样可以输出文本结果,更适合我放在笔记里。