root@MySQL-01 10:00:  [booboo]> select table_name,CHARACTER_SET_NAME,COLLATION_NAME from information_schema.columns where table_schema='booboo' and table_name='t2'; +------------+--------------------+--------------------+ | table_name | CHARACTER_SET_NAME | COLLATION_NAME     | +------------+--------------------+--------------------+ | t2         | NULL               | NULL               | | t2         | utf8mb4            | utf8mb4_unicode_ci | +------------+--------------------+--------------------+ 2 rows in set (0.00 sec)
  root@MySQL-01 10:01:  [booboo]> select table_name,CHARACTER_SET_NAME,COLLATION_NAME from information_schema.columns where table_schema='booboo' and table_name='t2'; +------------+--------------------+--------------------+ | table_name | CHARACTER_SET_NAME | COLLATION_NAME     | +------------+--------------------+--------------------+ | t2         | NULL               | NULL               | | t2         | utf8mb4            | utf8mb4_unicode_ci | +------------+--------------------+--------------------+ 2 rows in set (0.01 sec)
  root@MySQL-01 10:01:  [booboo]> select table_schema,table_name,COLUMN_NAME,CHARACTER_SET_NAME,COLLATION_NAME from information_schema.columns where table_schema='booboo' and table_name='t2'; +--------------+------------+-------------+--------------------+--------------------+ | table_schema | table_name | COLUMN_NAME | CHARACTER_SET_NAME | COLLATION_NAME     | +--------------+------------+-------------+--------------------+--------------------+ | booboo       | t2         | id          | NULL               | NULL               | | booboo       | t2         | name        | utf8mb4            | utf8mb4_unicode_ci | +--------------+------------+-------------+--------------------+--------------------+ 2 rows in set (0.00 sec)
  root@MySQL-01 10:02:  [booboo]> alter table t2  CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci; Query OK, 0 rows affected (0.05 sec) Records: 0  Duplicates: 0  Warnings: 0
  root@MySQL-01 10:02:  [booboo]> select table_schema,table_name,COLUMN_NAME,CHARACTER_SET_NAME,COLLATION_NAME from information_schema.columns where table_schema='booboo' and table_name='t2'; +--------------+------------+-------------+--------------------+-----------------+ | table_schema | table_name | COLUMN_NAME | CHARACTER_SET_NAME | COLLATION_NAME  | +--------------+------------+-------------+--------------------+-----------------+ | booboo       | t2         | id          | NULL               | NULL            | | booboo       | t2         | name        | utf8               | utf8_unicode_ci | +--------------+------------+-------------+--------------------+-----------------+ 2 rows in set (0.00 sec)
  root@MySQL-01 10:02:  [booboo]> show create table t2\G; *************************** 1. row ***************************        Table: t2 Create Table: CREATE TABLE `t2` (   `id` int(11) NOT NULL,   `name` varchar(10) COLLATE utf8_unicode_ci DEFAULT NULL,   PRIMARY KEY (`id`),   KEY `idx_name` (`name`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci 1 row in set (0.00 sec)
  ERROR: No query specified
  root@MySQL-01 10:03:  [booboo]> alter table t2  CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci; Query OK, 0 rows affected (0.04 sec) Records: 0  Duplicates: 0  Warnings: 0
  root@MySQL-01 10:03:  [booboo]> show create table t2\G; *************************** 1. row ***************************        Table: t2 Create Table: CREATE TABLE `t2` (   `id` int(11) NOT NULL,   `name` varchar(10) COLLATE utf8mb4_unicode_ci DEFAULT NULL,   PRIMARY KEY (`id`),   KEY `idx_name` (`name`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci 1 row in set (0.00 sec)
  ERROR: No query specified
  root@MySQL-01 10:03:  [booboo]> select table_schema,table_name,COLUMN_NAME,CHARACTER_SET_NAME,COLLATION_NAME from information_schema.columns where table_schema='booboo' and table_name='t2'; +--------------+------------+-------------+--------------------+--------------------+ | table_schema | table_name | COLUMN_NAME | CHARACTER_SET_NAME | COLLATION_NAME     | +--------------+------------+-------------+--------------------+--------------------+ | booboo       | t2         | id          | NULL               | NULL               | | booboo       | t2         | name        | utf8mb4            | utf8mb4_unicode_ci | +--------------+------------+-------------+--------------------+--------------------+ 2 rows in set (0.00 sec)
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