MySql 5.7 Функция UUID() съпоставяне по подразбиране - Незаконен микс от съпоставяне

(Това всъщност не е отговор, а опит да се изолира какво причинява проблема и какво може да го поправи.)

Влезте в DATABASE с напълно ирелевантен CHARACTER SET и COLLATION .

mysql> CREATE DATABASE `so40064402` /*!40100 DEFAULT CHARACTER SET ucs2 COLLATE ucs2_bin */
mysql> USE so40064402;
Database changed

Установете utf8_polish за клиента:

mysql> SET NAMES utf8 COLLATE utf8_polish_ci;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW VARIABLES LIKE 'c%a%t%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       | -- from SET NAMES
| character_set_connection | utf8                       | -- from SET NAMES
| character_set_database   | ucs2                       | -- from DATABASE
| character_set_filesystem | binary                     | -- (constant)
| character_set_results    | utf8                       | -- from SET NAMES
| character_set_server     | utf8mb4                    |
| character_set_system     | utf8                       | -- (constant)
| character_sets_dir       | /usr/share/mysql/charsets/ |
| collation_connection     | utf8_polish_ci             | -- from SET NAMES
| collation_database       | ucs2_bin                   | -- from DATABASE
| collation_server         | utf8mb4_unicode_520_ci     |
+--------------------------+----------------------------+
11 rows in set (0.00 sec)

mysql> select charset(uuid()), collation(uuid());
+-----------------+-------------------+
| charset(uuid()) | collation(uuid()) |
+-----------------+-------------------+
| utf8            | utf8_general_ci   |  -- part of the problem, but can't fix this
+-----------------+-------------------+
1 row in set (0.00 sec)

mysql> select replace(uuid(),'-','');
ERROR 1270 (HY000): Illegal mix of collations
                 (utf8_general_ci,COERCIBLE),
                 (utf8_polish_ci,COERCIBLE),
                 (utf8_polish_ci,COERCIBLE) for operation 'replace'
mysql> 
mysql> 
mysql> 
mysql> SET NAMES utf8mb4 COLLATE utf8mb4_polish_ci;
Query OK, 0 rows affected (0.00 sec)

Сега нека променим SET NAMES само. Сега работи!?? Въпреки UUID() е utf8 !?

mysql> SHOW VARIABLES LIKE 'c%a%t%';
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8mb4                    | -- from SET NAMES
| character_set_connection | utf8mb4                    | -- from SET NAMES
| character_set_database   | ucs2                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8mb4                    | -- from SET NAMES
| character_set_server     | utf8mb4                    |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
| collation_connection     | utf8mb4_polish_ci          | -- from SET NAMES
| collation_database       | ucs2_bin                   |
| collation_server         | utf8mb4_unicode_520_ci     |
+--------------------------+----------------------------+
11 rows in set (0.00 sec)

mysql> select replace(uuid(),'-','');
+----------------------------------+
| replace(uuid(),'-','')           |
+----------------------------------+
| ea841aacf83b11e8a66580fa5b3669ce |
+----------------------------------+
1 row in set (0.00 sec)

mysql>