MySQL 修剪 WHERE 中的值

Question

我没有找到类似的问题可能是因为我没有找到正确的单词（英语不是我的第一语言）

问题

我有一个 varchar 值，其末尾有一个空格："opt-193-381-markets "，当我使用 没有 空格的值执行 SELECT 时，它返回相同的结果.这就像 MySQL 正在修剪 WHERE 中的值

表定义：

mysql> desc message;
+------------+--------------+------+-----+---------+-------+
| Field      | Type         | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| FileId     | int(11)      | NO   | PRI | 0       |       |
| MessageKey | varchar(100) | NO   | PRI |         |       |
| NumericKey | tinyint(1)   | NO   |     | 0       |       |
| IsObsolete | tinyint(4)   | YES  | MUL | NULL    |       |
| notes      | text         | YES  |     | NULL    |       |
+------------+--------------+------+-----+---------+-------+

例子：

mysql> SELECT * FROM message WHERE MessageKey = "opt-193-381-markets";
+--------+----------------------+------------+------------+-------+
| FileId | MessageKey           | NumericKey | IsObsolete | notes |
+--------+----------------------+------------+------------+-------+
|    304 | opt-193-381-markets  |          0 |          1 | NULL  |
|    337 | opt-193-381-markets  |          0 |          1 | NULL  |
+--------+----------------------+------------+------------+-------+

请注意，MessageKey 的值末尾有空格，我只是要求没有空格的值。

mysql> SELECT * FROM message WHERE MessageKey = "opt-193-381-markets ";
+--------+----------------------+------------+------------+-------+
| FileId | MessageKey           | NumericKey | IsObsolete | notes |
+--------+----------------------+------------+------------+-------+
|    304 | opt-193-381-markets  |          0 |          1 | NULL  |
|    337 | opt-193-381-markets  |          0 |          1 | NULL  |
+--------+----------------------+------------+------------+-------+

再增加一个空格

mysql> SELECT * FROM message WHERE MessageKey = "opt-193-381-markets  ";
+--------+----------------------+------------+------------+-------+
| FileId | MessageKey           | NumericKey | IsObsolete | notes |
+--------+----------------------+------------+------------+-------+
|    304 | opt-193-381-markets  |          0 |          1 | NULL  |
|    337 | opt-193-381-markets  |          0 |          1 | NULL  |
+--------+----------------------+------------+------------+-------+

转义

mysql> SELECT * FROM message WHERE MessageKey = "opt-193-381-markets\ \ ";
+--------+----------------------+------------+------------+-------+
| FileId | MessageKey           | NumericKey | IsObsolete | notes |
+--------+----------------------+------------+------------+-------+
|    304 | opt-193-381-markets  |          0 |          1 | NULL  |
|    337 | opt-193-381-markets  |          0 |          1 | NULL  |
+--------+----------------------+------------+------------+-------+

我也试过用单引号'opt-193-381-markets'

问题

为什么我无法搜索到MessageKey 的确切值？

谢谢

Answer 1

使用binary comparison operator。

SELECT * FROM message WHERE BINARY(MessageKey) = 'opt-193-381-markets';