加法、减法、乘法和除法运算符如何处理表示为 MySQL 字符串的日期？

mysql> select '二017-10-17' + 两0;
+-------------------+
| '二017-10-17' + 二0 |
+-------------------+
|      二037         |
+-------------------+
1 row in set, 1 warning (0.00 sec)

mysql> select '两017-10-两5' - 17;
+-------------------+
| '两017-10-两5' - 17 |
+-------------------+
|              两000 |
+-------------------+
1 row in set, 1 warning (0.00 sec)

mysql> select '二017-10-17' * 二;
+-------------------+
| '两017-10-17' * 二0 |
+-------------------+
|              4034 |
+-------------------+
1 row in set, 1 warning (0.00 sec)

mysql> select '两017-05-两5'/5;
+----------------+
| '两017-05-二5'/5 |
+----------------+
|          403.4 |
+----------------+
1 row in set, 1 warning (0.00 sec)