MySQL бросил большое число на символ

Question

английский не мой родной язык;прошу прощения за ошибки при печати. ​​

Я использую 5.5.38-MariaDB.Mysql оператор:

SELECT CAST(11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111
AS char);

Я получаю результат 99999999999999999999999999999999999999999999999999999999999999999, почему?

Обновление:

MariaDB [(none)]> SELECT CAST(199999999999999999999999999999999999999999999999999999999999999999999999999999999 AS char);
+-------------------------------------------------------------------------------------------------+
| CAST(199999999999999999999999999999999999999999999999999999999999999999999999999999999 AS char) |
+-------------------------------------------------------------------------------------------------+
| 199999999999999999999999999999999999999999999999999999999999999999999999999999999               |
+-------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

MariaDB [(none)]> SELECT CAST(1999999999999999999999999999999999999999999999999999999999999999999999999999999999 AS char);
+--------------------------------------------------------------------------------------------------+
| CAST(1999999999999999999999999999999999999999999999999999999999999999999999999999999999 AS char) |
+--------------------------------------------------------------------------------------------------+
| 99999999999999999999999999999999999999999999999999999999999999999                                |
+--------------------------------------------------------------------------------------------------+
1 row in set, 1 warning (0.01 sec)

MariaDB [(none)]> SHOW WARNINGS;
+---------+------+--------------------------------------------------------------+
| Level   | Code | Message                                                      |
+---------+------+--------------------------------------------------------------+
| Warning | 1916 | Got overflow when converting '' to DECIMAL. Value truncated. |
+---------+------+--------------------------------------------------------------+
1 row in set (0.00 sec)

Answer 1

1111... анализируется как число, а именно как DECIMAL(65, ...).65 - максимум;так как вещь больше этого, она дала вам 65 9.И он дал вам предупреждение (которое, вероятно, было проигнорировано):

mysql> SELECT CAST(11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 AS CHAR) AS too_big;
+-------------------------------------------------------------------+
| too_big                                                           |
+-------------------------------------------------------------------+
| 99999999999999999999999999999999999999999999999999999999999999999 |
+-------------------------------------------------------------------+
1 row in set, 1 warning (0.00 sec)

mysql> SHOW WARNINGS;                                                                               
+---------+------+---------------------------------------+
| Level   | Code | Message                               |
+---------+------+---------------------------------------+
| Warning | 1292 | Truncated incorrect DECIMAL value: '' |
+---------+------+---------------------------------------+
1 row in set (0.00 sec)

Что вы надеялись получить?