问题描述
我在MySQL中有一个类型为decimal(3,2)的Justsomenum字段，当我插入类似78.3的值时，该字段似乎始终为9.99.为什么?
I have a field, justsomenum, of type decimal(3,2) in MySQL that seems to always have values of 9.99 when I insert something like 78.3. Why?
这是我的桌子的样子:
mysql> describe testtable;
+---------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| firstname | varchar(20) | YES | | NULL | |
| lastname | varchar(20) | YES | | NULL | |
| justsomenum | decimal(3,2) | YES | | NULL | |
+---------------+--------------+------+-----+---------+----------------+
当我插入这样的内容并选择时:
When I insert something like this and the select:
mysql> insert into testtable (firstname, lastname, justsomenum) values ("Lloyd", "Christmas", 83.5);
选择后我得到9.99.
I get 9.99 when I select.
mysql> select * from testtable;
+----+-----------+-----------+---------------+
| id | firstname | lastname | justsomenum |
+----+-----------+-----------+---------------+
| 1 | Shooter | McGavin | 9.99 |
| 2 | Lloyd | Christmas | 9.99 |
| 3 | Lloyd | Christmas | 9.99 |
| 4 | Lloyd | Christmas | 9.99 |
+----+-----------+-----------+---------------+
4 rows in set (0.00 sec)
这是Mac OS X 10.5.8上的MySQL 5.0.86.
This is MySQL 5.0.86 on Mac OS X 10.5.8.
有什么想法吗?谢谢.
推荐答案
decimal(3, 2)的最大值为9.99，因此，当您尝试插入大于该值的内容时，该最大值为9.99.如果要存储更大的数字，请尝试decimal(5, 2)或其他方法.
The maximum value for decimal(3, 2) is 9.99, so when you try to insert something larger than that, it is capped to 9.99. Try decimal(5, 2) or something else if you want to store larger numbers.
第一个参数是精度的位数，第二个参数是小数点后的位数.
The first argument is the total number of digits of precision, and the second argument is the number of digits after the decimal point.
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