Original sql field information:
koubei_desc text COMMENT 'Word of mouth description (optimal)'
Want to modify the encoding:
ALTER TABLE rank_sku CHANGE koubei_desc koubei_desc text COMMENT 'Word-of-mouth description (optimal)' CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

Why does SQL report an error after adding COMMENT 'Word of mouth description (optimal)'? Is it ok if I don’t add it? I want to add COMMENT 'Word of mouth description (optimal)', how to modify the SQL?