This question isn't easy. It's very ____ 发布时间:2017-06-28 14:02 │ 来源:www.tikuol.com 题型:选择题 问题: This question isn't easy. It's very _____. [ ]A. difficult B. difficulty C. easy D. not easy
题型:选择题 一个信息表student,要求它由学号sno,姓名sname,性别sex,年龄age,4个属性组成。现在对这个现有的表增加一个入学时间cometime字段为日期型,下列语句正确的是 ________。A.ALTER TABLE student ADD cometime DATE NOT NULL;B.ALTER TABLE student ADD cometime DATE;C.ALTER TABLE student DROP cometime DATE NOT NULL;D.ALTER TABLE student MODIFY cometime DATE; 查看答案