MySql - change collation

Changing database collation

ALTER DATABASE <database_name> CHARACTER SET utf8 COLLATE utf8_unicode_ci;

Changing table collation

ALTER TABLE <table_name> CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;

Changing column collation

ALTER TABLE <table_name> MODIFY <column_name> VARCHAR(255) CHARACTER SET utf8 COLLATE utf8_unicode_ci;