Cách xem character set của database / table / column trong MySQL?

Truy vấn INFORMATION_SCHEMA.

1. Character set của TABLE

SELECT CCSA.CHARACTER_SET_NAME
FROM INFORMATION_SCHEMA.TABLES T,
     INFORMATION_SCHEMA.COLLATION_CHARACTER_SET_APPLICABILITY CCSA
WHERE CCSA.COLLATION_NAME = T.TABLE_COLLATION
  AND T.TABLE_SCHEMA = 'TenDatabase'
  AND T.TABLE_NAME = 'TenBang';

mysql> SELECT CCSA.CHARACTER_SET_NAME
    -> FROM INFORMATION_SCHEMA.TABLES T,
    -> INFORMATION_SCHEMA.COLLATION_CHARACTER_SET_APPLICABILITY CCSA
    -> WHERE CCSA.COLLATION_NAME = T.TABLE_COLLATION
    -> AND T.TABLE_SCHEMA = "business"
    -> AND T.TABLE_NAME = "student";

+--------------------+
| CHARACTER_SET_NAME |
+--------------------+
| utf8mb4            |
+--------------------+
1 row in set (0.13 sec)

2. Character set của DATABASE

SELECT DEFAULT_CHARACTER_SET_NAME
FROM INFORMATION_SCHEMA.SCHEMATA
WHERE SCHEMA_NAME = 'TenDatabase';

mysql> SELECT DEFAULT_CHARACTER_SET_NAME
    -> FROM INFORMATION_SCHEMA.SCHEMATA
    -> WHERE SCHEMA_NAME = "business";

+----------------------------+
| DEFAULT_CHARACTER_SET_NAME |
+----------------------------+
| utf8mb4                    |
+----------------------------+
1 row in set (0.00 sec)

3. Character set của COLUMN

SELECT CHARACTER_SET_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'TenDatabase'
  AND TABLE_NAME = 'TenBang'
  AND COLUMN_NAME = 'TenCot';

mysql> SELECT CHARACTER_SET_NAME
    -> FROM INFORMATION_SCHEMA.COLUMNS
    -> WHERE TABLE_SCHEMA = "business"
    -> AND TABLE_NAME = "student"
    -> AND COLUMN_NAME = "Name";

+--------------------+
| CHARACTER_SET_NAME |
+--------------------+
| utf8mb4            |
+--------------------+
1 row in set (0.00 sec)