Question

我有一个varchar字段说值为174但是当我cast(field as decimal(3,1))它给我总是99.9？我如何将其转换或转换为17.4？或者我必须在源级别更改要以十进制形式输入的输入吗？

Answer 1

因为174不能用小数点之前的2位和小数点之后的1位表示。 decimal(3,1)表示＆＃34;总共3位数，小数点后1位（3位数）。

mysql> select cast('174' as decimal(3,1));
+-----------------------------+
| cast('174' as decimal(3,1)) |
+-----------------------------+
|                        99.9 |
+-----------------------------+
1 row in set, 1 warning (0.00 sec)

它会发出警告，可以显示：

mysql> show warnings;
+---------+------+----------------------------------------------------------------------+
| Level   | Code | Message                                                              |
+---------+------+----------------------------------------------------------------------+
| Warning | 1264 | Out of range value for column 'cast('174' as decimal(3,1))' at row 1 |
+---------+------+----------------------------------------------------------------------+
1 row in set (0.00 sec)

将数字除以10，然后重试：

mysql> select cast('174'/10 as decimal(3,1));
+--------------------------------+
| cast('174'/10 as decimal(3,1)) |
+--------------------------------+
|                           17.4 |
+--------------------------------+
1 row in set (0.00 sec)

Mysql转换为十进制给出99.9

1 个答案: