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  • mysql 字段添加以及删除

    mysql> select * from user;
    +------+-----------+-----------+
    | id   | name      | address   |
    +------+-----------+-----------+
    |    1 | xiaoming  | beijing   |
    |    2 | xiaobai   | shandong  |
    |    3 | xiaohong  | suzhou    |
    |    4 | xiaohei   | changchun |
    |    5 | xiaoli    | dongjing  |
    |    6 | xiaohuang | meiguo    |
    |    1 | xiaoming  | beijing   |
    |    1 | xiaoming  | beijing   |
    |    1 | xiaoming  | beijing   |
    +------+-----------+-----------+
    9 rows in set (0.00 sec)
    
    
    mysql> alter table user add ziduan char(10) null;
    Query OK, 0 rows affected (0.05 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    
    mysql> select * from user;
    +------+-----------+-----------+--------+
    | id   | name      | address   | ziduan |
    +------+-----------+-----------+--------+
    |    1 | xiaoming  | beijing   | NULL   |
    |    2 | xiaobai   | shandong  | NULL   |
    |    3 | xiaohong  | suzhou    | NULL   |
    |    4 | xiaohei   | changchun | NULL   |
    |    5 | xiaoli    | dongjing  | NULL   |
    |    6 | xiaohuang | meiguo    | NULL   |
    |    1 | xiaoming  | beijing   | NULL   |
    |    1 | xiaoming  | beijing   | NULL   |
    |    1 | xiaoming  | beijing   | NULL   |
    +------+-----------+-----------+--------+
    9 rows in set (0.00 sec)
    
    
    mysql> alter table user drop column ziduan;
    Query OK, 0 rows affected (0.06 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    
    mysql> select * from user;
    +------+-----------+-----------+
    | id   | name      | address   |
    +------+-----------+-----------+
    |    1 | xiaoming  | beijing   |
    |    2 | xiaobai   | shandong  |
    |    3 | xiaohong  | suzhou    |
    |    4 | xiaohei   | changchun |
    |    5 | xiaoli    | dongjing  |
    |    6 | xiaohuang | meiguo    |
    |    1 | xiaoming  | beijing   |
    |    1 | xiaoming  | beijing   |
    |    1 | xiaoming  | beijing   |
    +------+-----------+-----------+
    9 rows in set (0.00 sec)

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  • 原文地址:https://www.cnblogs.com/sea-stream/p/11312845.html
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