MariaDB將二進制轉換為int

Question

美好的一天！
我有一個帶有二進制列C1的表T1（在MariaDB中）。 它有一些字節。

當我選擇十六進制時，我有以下內容：

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

但我未能將結果轉換為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，我的問題是-為什么會發生，如何將二進制轉換為int？

Answer 1

類型為： 無符號整數或有符號整數

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

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