Mysql中对表字段的增删改查_MySQL

内容导读

互联网集市收集整理的这篇技术教程文章主要介绍了Mysql中对表字段的增删改查_MySQL，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含3880字，纯文字阅读大概需要6分钟。

内容图文

Mysql中对表字段的增删改查

mysql中对表字段的增加，修改（修改类型)，删除，排序

1.建立一个new 表，表中字段：学号，姓名，年龄。mysql> create table new (ne_id int(10),ne_name varchar(20),ne_age int(12));Query OK, 0 rows affected (0.97 sec)2.表的结构图mysql> desc new;+---------+-------------+------+-----+---------+-------+| Field   | Type        | Null | Key | Default | Extra |+---------+-------------+------+-----+---------+-------+| ne_id   | int(10)     | YES  |     | NULL    |       || ne_name | varchar(20) | YES  |     | NULL    |       || ne_age  | int(12)     | YES  |     | NULL    |       |+---------+-------------+------+-----+---------+-------+ rows in set (0.01 sec)3.向new 表中添加一个地址mysql> alter table new add ne_address varchar(20);Query OK, 0 rows affected (1.28 sec)Records: 0  Duplicates: 0  Warnings: 0mysql> desc new;+------------+-------------+------+-----+---------+-------+| Field      | Type        | Null | Key | Default | Extra |+------------+-------------+------+-----+---------+-------+| ne_id      | int(10)     | YES  |     | NULL    |       || ne_name    | varchar(20) | YES  |     | NULL    |       || ne_age     | int(12)     | YES  |     | NULL    |       || ne_address | varchar(20) | YES  |     | NULL    |       |+------------+-------------+------+-----+---------+-------+rows in set (0.00 sec)4.将字段名ne_id 改名为 ne_normysql> alter table new change ne_id ne_nor int(10);Query OK, 0 rows affected (0.22 sec)Records: 0  Duplicates: 0  Warnings: 0mysql> desc new;+------------+-------------+------+-----+---------+-------+| Field      | Type        | Null | Key | Default | Extra |+------------+-------------+------+-----+---------+-------+| ne_nor     | int(10)     | YES  |     | NULL    |       || ne_name    | varchar(20) | YES  |     | NULL    |       || ne_age     | int(12)     | YES  |     | NULL    |       || ne_address | varchar(20) | YES  |     | NULL    |       |+------------+-------------+------+-----+---------+-------+4 rows in set (0.00 sec)5.删除字段ne_nor mysql> alter table new drop ne_nor;Query OK, 0 rows affected (1.04 sec)Records: 0  Duplicates: 0  Warnings: 0mysql> desc new;+------------+-------------+------+-----+---------+-------+| Field      | Type        | Null | Key | Default | Extra |+------------+-------------+------+-----+---------+-------+| ne_name    | varchar(20) | YES  |     | NULL    |       || ne_age     | int(12)     | YES  |     | NULL    |       || ne_address | varchar(20) | YES  |     | NULL    |       |+------------+-------------+------+-----+---------+-------+3 rows in set (0.00 sec)6.修改字段类型：将ne_age 的 int 改为 varcharmysql> alter table new modify ne_age varchar(20);Query OK, 0 rows affected (1.34 sec)Records: 0  Duplicates: 0  Warnings: 0mysql> desc new;+------------+-------------+------+-----+---------+-------+| Field      | Type        | Null | Key | Default | Extra |+------------+-------------+------+-----+---------+-------+| ne_name    | varchar(20) | YES  |     | NULL    |       || ne_age     | varchar(20) | YES  |     | NULL    |       || ne_address | varchar(20) | YES  |     | NULL    |       |+------------+-------------+------+-----+---------+-------+3 rows in set (0.01 sec)7.排序mysql> alter table new modify ne_age varchar(20) after ne_address;Query OK, 0 rows affected (0.98 sec)Records: 0  Duplicates: 0  Warnings: 0mysql> desc new;+------------+-------------+------+-----+---------+-------+| Field      | Type        | Null | Key | Default | Extra |+------------+-------------+------+-----+---------+-------+| ne_name    | varchar(20) | YES  |     | NULL    |       || ne_address | varchar(20) | YES  |     | NULL    |       || ne_age     | varchar(20) | YES  |     | NULL    |       |+------------+-------------+------+-----+---------+-------+3 rows in set (0.00 sec)

内容总结

以上是互联网集市为您收集整理的Mysql中对表字段的增删改查_MySQL全部内容，希望文章能够帮你解决Mysql中对表字段的增删改查_MySQL所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错，欢迎将互联网集市网站推荐给程序员好友。

内容备注

版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 gblab@vip.qq.com 举报，一经查实，本站将立刻删除。

内容手机端