MYSQL Concat无法正常工作

Question

UPDATE配置文件SET favourties = CONCAT(favourties,"123")WHERE id = 1

我想在favourties中添加123,但如果favourties的默认值设置为NULL,则此查询将不起作用.如果favourties设置为NULL然后用它附加123,将会查询什么

Answer 1

UPDATE profile SET favourties=CONCAT(IFNULL(favourties, ''),"123") WHERE id=1

Answer 2

使用以下COALESCE功能包裹场地:

UPDATE profile
SET favourties = CONCAT(COALESCE(favourties, ''),"123")
WHERE id=1