mysql - 忽略类型转换 IN

Question

我有问题。

mysql> SELECT 0 IN ('a',4);
+--------------+
| 0 IN ('a',4) |
+--------------+
|            1 |
+--------------+
1 row in set, 1 warning (0.00 sec)

mysql> SELECT 1 IN ('a',4);
+--------------+
| 1 IN ('a',4) |
+--------------+
|            0 |
+--------------+
1 row in set, 1 warning (0.00 sec)

'a' 转换为 0。如何使 'a' 不被转换..？

Answer 1

将要比较的值转换为字符串:

mysql> SELECT '0' IN ('a', '4');
+-----------------+
| '0' IN ('a', 4) |
+-----------------+
|               0 |
+-----------------+

mysql> SELECT '4' IN ('a', '4');
+-----------------+
| '4' IN ('a', 4) |
+-----------------+
|               1 |
+-----------------+