mysql基础(5)_列类型之整形、显示长度(zerofill)_1.2列类型——显示长度(zerofill)

列类型(字段类型)

整数类型
Tinyint
迷你整形，系统采用一个字节来保存的整形:一个字节 =8位，最大能表示的数值是0-255
Smallint
小整形,系统采用两个字节来保存的整形:能表示0-65535之间
Mediumint
中整形，采用三个字节来保存数据
Int
整形(标准整形),采用四个字节来保存数据
Bigint
大整形，采用八个字节来保存数据

mysql> create table int_data(
    -> int_1 tinyint,
    -> int_2 smallint,
    -> int_3 mediumint,
    -> int_4 int,
    -> int_5 bigint);
Query OK, 0 rows affected (0.14 sec)
 
mysql> insert into int_data values(10,10000,100000,10000000,1000000000);
Query OK, 1 row affected (0.11 sec)
 
mysql> select * from int_data;
+-------+-------+--------+----------+------------+
| int_1 | int_2 | int_3  | int_4    | int_5      |
+-------+-------+--------+----------+------------+
|    10 | 10000 | 100000 | 10000000 | 1000000000 |
+-------+-------+--------+----------+------------+
1 row in set (0.00 sec)
 
-- 1 warning 插入数据超出范围，tinyint默认为整形增加负数，实际表示的区间为-128-127
mysql> insert into int_data values(255,255,255,255,255);
Query OK, 1 row affected, 1 warning (0.00 sec)
 
mysql> insert into int_data values(-128,255,255,255,255);
Query OK, 1 row affected (0.04 sec)
 
mysql> select * from int_data;
+-------+-------+--------+----------+------------+
| int_1 | int_2 | int_3  | int_4    | int_5      |
+-------+-------+--------+----------+------------+
|    10 | 10000 |