在 MySQL 中使用十六进制数字？

SET anyVariableName = CONV(yourHexValue,16,10);

mysql> DELIMITER //
mysql> CREATE PROCEDURE SP_HEX_TO_DEC( HEXVALUE VARCHAR(10) )
   -> BEGIN
   -> DECLARE Decimalvalue INTEGER;
   -> SET Decimalvalue = CONV(HEXVALUE,16,10);
   -> select Decimalvalue;
   -> END;
   -> //
Query OK, 0 rows affected (0.19 sec)
mysql> DELIMITER ;

CALL yourStoredProcedureName;

mysql> call SP_HEX_TO_DEC('A');

+--------------+
| Decimalvalue |
+--------------+
| 10           |
+--------------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.01 sec)

mysql> select conv('AB',16,10) as DecimalResult;

+---------------+
| DecimalResult |
+---------------+
| 171           |
+---------------+
1 row in set (0.00 sec)

A and B represented as 10 and 11 respectively in hexadecimal.
To convert it into decimal rule is as follows:
N ………+value3 *162 +value2 *161 + value1 * 160
= 10 * 161 + 11 * 160
= 160+11
= 171.