第1题
Ⅰ . π sname (σ dept= ’ IS ’ ∧ age<20(STUDENT ))
Ⅱ . σ dept= ’ IS ’ ∧ age<20 (π sname (STUDENT ))
Ⅲ . σ sname (π dept= ’ IS ’ ∧ age<20(STUDENT ))
A )仅 Ⅰ
B )仅 Ⅱ
C ) Ⅰ 和 Ⅱ
D ) Ⅱ 和 Ⅲ
第2题
A)仅Ⅰ
B)仅Ⅱ
C)Ⅰ和Ⅱ
D)Ⅱ和Ⅲ
第3题
A)仅Ⅰ
B)仅Ⅱ
C)Ⅰ和Ⅱ
D)Ⅱ和Ⅲ
第4题
设有学生数据库:student(sno,sname,sex,age,dept)。现要查询所有刘姓学生的信息,可使用如下的 SQL语句:SELECT*FROM student WHERE【 】。
第5题
对于学生信息表:student(sno,sname,sex,age,dept),能够得到年龄在20岁到22岁之间的学生的姓名和学号的语句是
A.SELECT*FROM student WHERE age BETWEEN 20 AND 22
B.SELECT sname,sno FROM student WHERE age BETWEEN 20 AND 22
C.SELECT sname,sno FROM student WHERE age>=20
D.SELECT sname,sno FROM student WHERE age<=22
第6题
对于学生信息表:student(sno,sname,sex,age,dept),能够得到年龄在20岁于22岁之间的学生的姓名和学号的语句是
A.SELECT * FROM student WHERE age BETWEEN 20 AND 22
B.SELECT sname,sno FROM student WHERE age BETWEEN 20 AND 22
C.SELECT sname,sno FROM student WHERE age>=20
D.SELECT sname,sno FROM student WHERE age<=22
第7题
对于学生信息表:student(sno,sname,sex,age,dept),能够得到年龄在20岁到22岁之间的学生的姓名和学号的语句是
A.SELECT * FROM student WHERE age BETWEEN 20 AND 22
B.SELECT sname,sno FROM student WHERE age BETWEEN 20 AND 22
C.SELECT sname,sno FROM student WHERE age>=20
D.SELECT sname,sno FROM student WHERE age<=22
第8题
第9题
A.П2, 5(S)
B.σ2, 5(S)
C.ПSNAME, DEPT(S)
D.σSNAME, DEPT(S)
第10题
A.П2, 5(S)
B.σ2, 5(S)
C.ПSNAME, DEPT(S)
D.σSNAME, DEPT(S)
为了保护您的账号安全,请在“上学吧”公众号进行验证,点击“官网服务”-“账号验证”后输入验证码“”完成验证,验证成功后方可继续查看答案!