MySql 数据类型 - 小数型

使用效果

定义三个字段分别为 float、double 和 decimal 类型，并都插入数字 123456789.123456789123456789 显示结果，注意三者保留数值精度也不一样。

mysql> desc user;
+-------+----------------+------+-----+---------+-------+
| Field | Type           | Null | Key | Default | Extra |
+-------+----------------+------+-----+---------+-------+
| x1    | float          | YES  |     | NULL    |       |
| x2    | double         | YES  |     | NULL    |       |
| x3    | decimal(23,14) | YES  |     | NULL    |       |
+-------+----------------+------+-----+---------+-------+
mysql> insert into user (x1, x2, x3) values (123456789.123456789123456789, 123456789.123456789123456789, 123456789.123456789123456789);
mysql> select * from user;
+-----------+--------------------+--------------------------+
| x1        | x2                 | x3                       |
+-----------+--------------------+--------------------------+
| 123457000 | 123456789.12345679 | 123456789.12345678912346 |
+-----------+--------------------+--------------------------+