Mysql 简明教程
MySQL - TINYINT
The MySQL TINYINT Data Type
MySQL TINYINT 数据类型用于将整数值存储在非常小的范围内。它仅占用 1 字节（8 位）存储，对于有符号的 TINYINT 来说可以容纳 -128 到 127 的值，对于无符号的 TINYINT 来说可以容纳 0 到 255 的值。
The MySQL TINYINT data type is used to store integer values within a very small range. It occupies just 1 byte (8 bits) of storage and can hold values from -128 to 127 for signed TINYINT or 0 to 255 for unsigned TINYINT.
当你在 MySQL 中定义一个 TINYINT 列时，默认情况下它被认为是有符号的。这意味着它可以在特定范围内容纳正数和负数。此外，你可以使用“TINYINT”或“INT1”来定义这种列，因为它们以相同的方式工作。
When you define a TINYINT column in MySQL, by default it is considered as SIGNED. This means it can hold both positive and negative numbers within a specific range. Additionally, you can use either "TINYINT" or "INT1" to define such a column because they work the same way.
Syntax
以下是 MySQL TINYINT 数据类型的语法 -
Following is the syntax of the MySQL TINYINT data type −
TINYINT(M) [SIGNED | UNSIGNED | ZEROFILL]Example
首先，让我们使用以下查询创建一个名为 tinyint_table 的表 -
First, let us create a table with the name tinyint_table using the below query −
CREATE TABLE tinyint_table (
col1 TINYINT,
col2 TINYINT UNSIGNED,
col3 TINYINT ZEROFILL
);以下是所获得的输出 −
Following is the output obtained −
Query OK, 0 rows affected, 1 warning (0.03 sec)现在，让我们尝试将某些值（128、128、128）插入这些列，如下所示 -
Now, let us try to insert some values (128, 128, 128) into these columns as shown below −
INSERT INTO tinyint_table VALUES (128, 128, 128);col1 中的值会生成错误，因为我们插入的值超出了范围 -
An error is generated for the value in col1 because the value we inserted is out of range −
ERROR 1264 (22003): Out of range value for column 'col1' at row 1接下来，如果我们尝试在 TINYINT UNSIGNED 列 (“col2”) 中插入一个负值，它将导致错误，因为 UNSIGNED 值不能是负数 -
Next, if we try to insert a negative value into the TINYINT UNSIGNED column ("col2"), it will result in an error because UNSIGNED values cannot be negative −
INSERT INTO tinyint_table VALUES (127, -120, 128);显示的错误信息如下 -
The error message displayed is as follows −
ERROR 1264 (22003): Out of range value for column 'col2' at row 1同样，如果我们将 -128 插入 TINYINT ZEROFILL 列 (“col3”)，系统会生成一个错误 −
Similarly, if we insert -128 into the TINYINT ZEROFILL column ("col3"), an error will be generated −
INSERT INTO tinyint_table VALUES (127, 128, -128);输出如下所示：
The output is as shown below −
ERROR 1264 (22003): Out of range value for column 'col3' at row 1但是，如果我们插入有效范围内的值，插入操作会成功，如下所示 −
However, if we insert values within the valid range, the insertion will succeed as shown below −
INSERT INTO tinyint_table VALUES (127, 128, 128);以下是上面代码的输出： -
Following is the output of the above code −
Query OK, 1 row affected (0.01 sec)最后，我们可以使用以下 SELECT 查询检索表中所有已有的记录 −
Finally, we can retrieve all the records present in the table using the following SELECT query −
SELECT * FROM tinyint_table;该查询将显示以下结果 −
This query will display the following result −