首页 > 资讯 > 其他综合 > 正文

数据类型之【数值类型】的整数型tinyint

19-01-21 来源：[db:作者]

收藏我要投稿

1.1 tinyint说明

id tinyint(M) [UNSIGNED] [ZEROFILL]

字段名字段类型(长度) [无符号] [前导填充]

unsigned：

01：tinyint(M)后面加上unsigned参数后,就是无符号(tinyint范围就是0~255)

02：tinyint(M)后面不加unsigned参数,且不加zerofill参数,就是有符号(tinyint范围就是-128~127)

zerofill：

01：进行前导零填充

02：tinyint(M)加上zerofile后，同时也会把unsigned参数也带上(tinyint范围0~255)

1.2 tinying实践

1.2.1 环境准备

##创建chenliang库

mysql> create database if not exists chenliang;

Query OK, 1 row affected (0.03 sec)

mysql> show databases like "chenliang";

+----------------------+

| Database (chenliang) |

+----------------------+

| chenliang |

+----------------------+

1 row in set (0.03 sec)

##进入chenliang库

mysql> use chenliang;

Database changed

mysql> select database();

+------------+

| database() |

+------------+

| chenliang |

+------------+

1 row in set (0.01 sec)

1.2.2 加unsigned参数

##创建test1测试表(这里指定了UNSIGNED，也就是无符号)

mysql> CREATE TABLE IF NOT EXISTS test1(

-> id tinyint(3) UNSIGNED

-> );

Query OK, 0 rows affected (0.06 sec)

^==表test1的id字段加了unsigned参数，那么id字段的范围就是0~255

mysql> desc test1;

+-------+---------------------+------+-----+---------+-------+

+-------+---------------------+------+-----+---------+-------+

| id | tinyint(3) unsigned | YES | | NULL | |

+-------+---------------------+------+-----+---------+-------+

1 row in set (0.03 sec)

****测试01：测试插入范围0~255的正整数和超过255的正整数

mysql> INSERT INTO test1 values(0); #插入数值0,正常(没有超过范围)

Query OK, 1 row affected (0.06 sec)

mysql> INSERT INTO test1 values(255); #插入数值255,正常(没有超过范围)

Query OK, 1 row affected (0.05 sec)

mysql> INSERT INTO test1 values(256); #插入数值256,错误(超过了tinyint的范围)

ERROR 1264 (22003): Out of range value for column 'id' at row 1

mysql> select * from test1;

+------+

| id |

+------+

| 0 |

| 255 |

+------+

2 rows in set (0.00 sec)

***测试02：测试插入范围-1~-128范围的负整数

mysql> INSERT INTO test1 values(-1); #插入负整数-1,报错

ERROR 1264 (22003): Out of range value for column 'id' at row 1

mysql> INSERT INTO test1 values(-128); #插入负整数-128,报错

ERROR 1264 (22003): Out of range value for column 'id' at row 1

mysql> INSERT INTO test1 values(-129); #插入负整数-129,报错

ERROR 1264 (22003): Out of range value for column 'id' at row 1

mysql> select * from test1;

+------+

| id |

+------+

| 0 |

| 255 |

+------+

2 rows in set (0.00 sec)

1.2.3 加zerofill参数

##创建test2表(这里指定了zerofill,也就是前导零填充)

mysql> CREATE TABLE IF NOT EXISTS test2(

-> id tinyint(3) ZEROFILL

-> );

Query OK, 0 rows affected (0.07 sec)

^==表test2的id字段加了zerofill参数，那么id字段的范围为0~255，因为加

上了zerofill参数后，会同时把unsigned参数也带上

mysql> desc test2;

+-------+------------------------------+------+-----+---------+-------+

+-------+------------------------------+------+-----+---------+-------+

| id | tinyint(3) unsigned zerofill | YES | | NULL | |

+-------+------------------------------+------+-----+---------+-------+

1 row in set (0.00 sec)

****测试01：测试插入范围0~255的正整数和超过255的整数

mysql> INSERT INTO test2 values(0); #插入数值0,正常(没有超过范围)

Query OK, 1 row affected (0.01 sec)

mysql> INSERT INTO test2 values(255); #插入数值255,正常(没有超过范围)

Query OK, 1 row affected (0.08 sec)

mysql> INSERT INTO test2 values(256); #插入数值256,错误(超过范围)

ERROR 1264 (22003): Out of range value for column 'id' at row 1

mysql> select * from test2;

+------+

| id |

+------+

| 000 |

| 255 |

+------+

2 rows in set (0.00 sec)

***测试02：测试插入-1~-128范围的负整数

mysql> INSERT INTO test2 values(-1); #插入负整数-1,报错

ERROR 1264 (22003): Out of range value for column 'id' at row 1

mysql> INSERT INTO test2 values(-128); #插入负整数-128,报错

ERROR 1264 (22003): Out of range value for column 'id' at row 1

mysql> INSERT INTO test2 values(-129); #插入负整数-129,报错

ERROR 1264 (22003): Out of range value for column 'id' at row 1

mysql> select * from test2;

+------+

| id |

+------+

| 000 |

| 255 |

+------+

2 rows in set (0.00 sec)

1.2.4 不加unsigned和zerofill参数

##创建test3表(不加unsigned和zerofill)

mysql> CREATE TABLE test3(

-> id tinyint(3)

-> );

Query OK, 0 rows affected (0.06 sec)

^==表test3的id字段没有加unsigned和zerofill参数，那么id字段的范围为

-128~127

mysql> desc test3;

+-------+------------+------+-----+---------+-------+

+-------+------------+------+-----+---------+-------+

| id | tinyint(3) | YES | | NULL | |

+-------+------------+------+-----+---------+-------+

1 row in set (0.01 sec)

****测试01：测试插入0~127的正整数和超过127的正整数

mysql> INSERT INTO test3 values(0);

Query OK, 1 row affected (0.05 sec)

mysql> INSERT INTO test3 values(128);

ERROR 1264 (22003): Out of range value for column 'id' at row 1

mysql> select * from test3;

+------+

| id |

+------+

| 0 |

+------+

1 row in set (0.01 sec)

***测试02：测试插入-1~-128的负整和小于-128的负整数

mysql> INSERT INTO test3 values(-1);

Query OK, 1 row affected (0.10 sec)

mysql> INSERT INTO test3 values(-128);

Query OK, 1 row affected (0.02 sec)

mysql> INSERT INTO test3 values(-129);

ERROR 1264 (22003): Out of range value for column 'id' at row 1

mysql> select * from test3;

+------+

| id |

+------+

| 0 |

| -1 |

| -128 |

+------+

3 rows in set (0.00 sec)

1.3 tinyint总结

格式：

id tinyint(M) [UNSIGNED] [ZEROFILL]

字段名字段类型(长度) [无符号] [前导填充]

unsigned：

01：tinyint(M)后面加上unsigned参数后,就是无符号(tinyint范围就是0~255)

02：tinyint(M)后面不加上unsigned参数,且不加zerofill参数,就是有符号(tinyint范围就是-128~127)

zerofill：

01：进行前导零填充(插入数值1，表中显示的是001，因为tinyint的长度为3)

02：tinyint(M)加上zerofile后，同时也会把unsigned参数也带上(tinyint的范围是0~255)

点击复制链接与好友分享!回本站首页