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在MySQL中将tinyint的默认值更改为1？

2024-05-17 00:10:05 389

您可以为此使用DEFAULT命令。以下是语法-

alter table yourTableName change yourColumnName yourColumnName TINYINT(1) DEFAULT 1 NOT NULL;

让我们首先创建一个表-

mysql> create table DemoTable
(
   Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   UserName varchar(20),
   UserAge int,
   isMarried tinyint(1)
);

让我们检查表的描述-

mysql> desc DemoTable;

这将产生以下输出-

+-----------+-------------+------+-----+---------+----------------+
| Field     | Type        | Null | Key | Default | Extra          |
+-----------+-------------+------+-----+---------+----------------+
| Id        | int(11)     | NO   | PRI | NULL    | auto_increment |
| UserName  | varchar(20) | YES  |     | NULL    |                |
| UserAge   | int(11)     | YES  |     | NULL    |                |
| isMarried | tinyint(1)  | YES  |     | NULL    |                |
+-----------+-------------+------+-----+---------+----------------+
4 rows in set (0.21 sec)

以下是将tinyint默认值更改为1的查询-

mysql> alter table DemoTable change isMarried isMarried TINYINT(1) DEFAULT 1 NOT NULL;
Records: 0 Duplicates: 0 Warnings: 0

让我们再次检查表的描述。tinyint的默认值已更改为1-

mysql> desc DemoTable;

这将产生以下输出-

+-----------+-------------+------+-----+---------+----------------+
| Field     | Type        | Null | Key | Default | Extra          |
+-----------+-------------+------+-----+---------+----------------+
| Id        | int(11)     | NO   | PRI | NULL    | auto_increment |
| UserName  | varchar(20) | YES  |     | NULL    |                |
| UserAge   | int(11)     | YES  |     | NULL    |                |
| isMarried | tinyint(1)  | NO   |     | 1       |                |
+-----------+-------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

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在MySQL中将tinyint的默认值更改为1？

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