MariaDB 将二进制转换为 int

Question

美好的一天！
我有一个带有二进制列 C1 的表 T1（在 MariaDB）。它有一些字节。

当我选择 HEX 时，我有以下内容：

select HEX(SUBSTRING((select C1 from T1 where <some restrictions>), 254, 2));
+----------------------------------------------------------------------+
| HEX(SUBSTRING((select C1 from T1 where <some restrictions>), 254, 2)) |
+----------------------------------------------------------------------+
| 1200                                                                 |
+----------------------------------------------------------------------+

但我未能将结果转换为 INT：

select cast((SUBSTRING((select C1 from T1 where <some restrictions>), 254, 2)) as int);
+--------------------------------------------------------------------------------+
| cast((SUBSTRING((select C1 from T1 where <some restrictions>), 254, 2)) as int) |
+--------------------------------------------------------------------------------+
|                                                                              0 |
+--------------------------------------------------------------------------------+

所以，我的问题是 - 为什么会发生以及如何将二进制转换为 int？

Answer 1

类型为：无符号整数或有符号整数

select cast((substring((select C1 from T1 where <some restrictions>), 254, 2)) as unsigned integer);

select cast(substring( '12345', 1, 2 ) as unsigned integer)