mysql_charset.mysql

# Show database charset
SELECT default_character_set_name FROM information_schema.SCHEMATA 
 WHERE schema_name = "<database>";

# Chase database charset
ALTER DATABASE <database> CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;

# Show table charset
SELECT CCSA.character_set_name, T.table_name FROM information_schema.`TABLES` T,
       information_schema.`COLLATION_CHARACTER_SET_APPLICABILITY` CCSA
 WHERE CCSA.collation_name = T.table_collation
   AND T.table_schema = "<database>";

# Change table charset
ALTER TABLE <table> CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

# Show column charset
SELECT table_name, column_name, character_set_name FROM information_schema.`COLUMNS`
 WHERE table_schema = "<database>";

# Change column charset
ALTER TABLE <table> CHANGE <column> <column> <type, e.g. VARCHAR(191)> CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;