如何检查插入触发器中的字段是否为空？

Question

如何在触发器中验证在 table 中插入数据之前是否在字段中未插入任何内容，即它为空。如何检查它在触发器中是否为空？

我试过这样验证过，但是没有进入字段为null的条件

DELIMITER //
CREATE TRIGGER tr_i_correo BEFORE INSERT ON examen_final
FOR EACH ROW
BEGIN

IF correo IS NULL THEN
    SET new.correo = 'jatuesta@mail.com');
END IF; 

END //

Answer 1

New.crreo 也应该测试空字符串

CREATE TABLE examen_final (correo varchar(199), nome varchar(100))

CREATE TRIGGER tr_i_correo BEFORE INSERT ON examen_final
FOR EACH ROW
BEGIN

IF NEW.correo IS NULL OR NEW.correo = '' THEN
    SET new.correo = 'jatuesta@mail.com';
END IF; 

END

INSERT INTO examen_final VALUEs (NULL, 'test1'), ('', 'test2')

SELECT * FROM examen_final

correo            | nome 
:---------------- | :----
jatuesta@mail.com | test1
jatuesta@mail.com | test2

db<>fiddle here

如何检查插入触发器中的字段是否为空？

How to check a field is null in an insert trigger?

mysql

triggers