• 2022-06-04
    已知有关系“STUDENT”,则关系运算σANE<80(STUDENT)用SQL语句表示为 (52) 。
    A: SELECT( * )FROM STUDENT WHERE AVE < 80
    B: SELECT( * ) FROM STUDENT HAVING AVE < 80
    C: SELECT(AVE) FROM STUDENT WHERE AVE < 80
    D: SELECT(AVE) FROM STUDENT HAVING AVE < 80
  • A

    举一反三

    内容

    • 0

      使用教学(STC)数据库,与如下查询语句等价的是( )。 SELECT *FROM Student WHERE Sdept = 'CS' EXCEPT SELECT * FROM Student WHERE Sage <= 19; A: SELECT * FROM Student WHERE Sdept = 'CS' AND Sage > 19 B: SELECT * FROM Student WHERE Sdept = 'CS' AND Sage <= 19 C: SELECT * FROM Student WHERE Sdept = 'CS' OR Sage <= 19 D: SELECT * FROM Student WHERE Sdept = 'CS' OR Sage > 19

    • 1

      在所有学生中查询比计算机系学生平均年龄大的学生姓名,可以使用的查询语句是: A: SELECT Sname FROM Student WHERE Sage > ( SELECT AVG(Sage) FROM Student ); WHERE Sdept = 'CS' B: SELECT Sname FROM Student WHERE Sage > AVG( SELECT Sage FROM Student WHERE Sdept = 'CS' ); C: SELECT Sname FROM Student WHERE Sage > ( SELECT AVG(Sage) FROM Student WHERE Sdept = 'CS' ); D: SELECT Sname FROM Student WHERE AVG(Sage) > ( SELECT Sage FROM Student WHERE Sdept = 'CS' );

    • 2

      ‍从Student表检索姓周的学生,对应的SQL语句是( )。‍ A: Select * From Student Where Sname like '周%' B: Select * From Student Where Sname like '%周' C: Select * From Student Where Sname like '_周' D: Select * From Student Where Sname like '周_'

    • 3

      从学生表student查询所有女学生的信息,正确的语句是( )。 A: SELECT B: FROM student where 性别="女"; C: SELECT * FROM student where 性别="女"; D: SELECT ? FROM student where 性别="女"; E: SELECT FROM student where 性别="女";

    • 4

      从Student表检索年龄为20岁的学生信息,已知年龄字段是数值类型,最规范的SQL语句是( )。 A: Select * From Student where Sage=20 B: Select * From Student where Sage='20' C: Select * From Student where Sage=【20】 D: Select * From Student where Sage EQUAL 20