mysql - 你好mysql更新

Question

嗨，如果名字是 harpo，姓氏是 Williamns，我想将名字更改为 grouocho，其他虎钳我想更改为名字是 Harpo 的 Mocho Groucho。当我运行我的代码时，它给了我

Error   1175    You are using safe update mode and you tried to 
update a table without a WHERE that uses a KEY column

任何人都可以帮助我吗？

UPDATE actor
SET first_name = 
CASE 
    WHEN first_name = 'HARPO' AND last_name = 'Williams' THEN 'GROUCHO'
    WHEN first_name = 'HARPO' AND last_name != 'Williams' THEN 'MOCHO GROUCHO'
END
;