基数必须大于 2 且小于 36，即基数的下限为 2，上限为 36。它适用于 from_base 和 to_base 值。如果我们提供的值超出了基数的限制，那么 MySQL 将返回 NULL 作为输出。以下示例将演示它 -
示例
mysql> Select CONV(10,10,38);
+----------------+
| CONV(10,10,38) |
+----------------+
| NULL |
+----------------+
1 row in set (0.00 sec)
mysql> Select CONV(10,72,2);
+---------------+
| CONV(10,72,2) |
+---------------+
| NULL |
+---------------+
1 row in set (0.00 sec)
mysql> Select CONV(10,10,1);
+---------------+
| CONV(10,10,1) |
+---------------+
| NULL |
+---------------+
1 row in set (0.00 sec)
