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；

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: AITER 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 MODIPY cometime DATE;

返回两个日期间隔天数的函数是（） A: datediff B: date_format C: year D: date_add

The custom _______ the Middle Ages. A: date on B: date about C: date from D: date in

查询十天前的记录应使用( )作为准则。 A: Between Date() And Date()-10 B: ＜Date()-10 C: ＞Date()-10 D: Between Date()-10 And Date()

In appraisals, the effective date of value is ( ). A: The date of the property inspection B: The date agreed in advance with the client C: The date the appraisal is completed D: The date the appraisal is signed

查询最后30天的记录应使用（ ）作为准则。 A: Between Date() and Date()-30 B: <=Date()-30 C: <Date()-30 D: Between Date()-30 and Date()

________ is known to all，good friends _________ happiness and value to life. A: It; add B: As; add C: It; add up D: As; add to

Congratulations! This is the best book you have written __________. A: up to date B: out of date C: to date D: as date

下列能获取date命令结果的语句是（ ）。 A: $(date) B: `dae` C: （date) D: date'