建表时怎么设置字段不能为空

Question

runoob_tbl(
   runoob_id INT NOT NULL AUTO_INCREMENT,
   runoob_title VARCHAR(100) NOT NULL,
   runoob_author VARCHAR(40) NOT NULL,
   submission_date DATE,
   PRIMARY KEY ( runoob_id ));

这样只是字段不能为null，但是可以是空白，怎么设置必须有值

Answer 1

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

Answer 2

可以添加一个默认值，default 'value'，或者定义为enum类型

Answer 3

not null default ‘’