zoukankan      html  css  js  c++  java
  • mysql中列的增删改

    增加列:
    alter table table_name add name varchar(100);
    alter table table_name add name varchar(100) after id;
    alter table table_name add name varchar(100) first;
    
    修改列名:
    
    alter table table_name change name name varchar(10);
    #change可改名字与字段类型
    mysql> alter table a change uid uid int;
    Query OK, 0 rows affected (0.04 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    alter table table_name modify name int;
    #modify只改字段类型
    mysql> desc a;
    +-------+---------+------+-----+---------+-------+
    | Field | Type    | Null | Key | Default | Extra |
    +-------+---------+------+-----+---------+-------+
    | namea | char(1) | YES  |     | NULL    |       |
    | id    | int(11) | YES  |     | NULL    |       |
    | uid   | int(11) | YES  |     | NULL    |       |
    +-------+---------+------+-----+---------+-------+
    3 rows in set (0.01 sec)
    
    mysql>
    mysql>
    mysql> alter table a modify uid varchar(1);
    Query OK, 0 rows affected (0.07 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    mysql> desc a;
    +-------+------------+------+-----+---------+-------+
    | Field | Type       | Null | Key | Default | Extra |
    +-------+------------+------+-----+---------+-------+
    | namea | char(1)    | YES  |     | NULL    |       |
    | id    | int(11)    | YES  |     | NULL    |       |
    | uid   | varchar(1) | YES  |     | NULL    |       |
    +-------+------------+------+-----+---------+-------+
    3 rows in set (0.01 sec)
    
    mysql>
    
    删除列:
    alter table table_name drop column_name;
    
    
    #手册
    help modify;
  • 相关阅读:
    HTML-参考手册: HTTP 状态消息
    HTML-参考手册: HTML 语言代码
    HTML-参考手册: URL 编码
    HTML-参考手册: HTML 符号实体
    HTML-参考手册: HTML ISO-8859-1
    HTML-参考手册: HTML ASCII
    HTML-参考手册: HTML 字符集
    HTML-参考手册: 颜色混搭
    HTML-参考手册: HTML 拾色器
    HTML-参考手册: HTML 颜色名
  • 原文地址:https://www.cnblogs.com/perl6/p/7113182.html
Copyright © 2011-2022 走看看