举一反三
- 查询选修了课程号为'C2'的学生号和姓名，若用下列SQL的SELECT语句表达时，哪一个是错误的？（） A: SELECT S#，SNAME FROM S WHERE S# = (SELECT SS# FROM SC WHERE C# = 'C2' ) B: SELECT S#，SNAME FROM S，SCWHERE S# = SS# AND C# = 'C2' C: SELECT S#，SNAME FROM S，SC WHERE S# = SS# AND C# = 'C2' ORDER BY S# D: SELECT S#，SNAME FROM S WHERE S# IN (SELECT SS# FROM SC WHERE C# ='C2' )
- 查询选修了课程号为C2的学生号和姓名，用下列SQL的SELECT语句表达时，哪一个是错误的( ) A: SELECT S.S#，SNAME FROM S WHERE S.S# B: =(SELECT SC) S# FROM SC WHERE C#=‘C2’) C: SELECT S.S#，SNAME FROMS，SC D: WHERE S.S# S E: S# AND C#=‘C2’C) SELECT S. S#，SNAME FROM S，SC F: WHERE S.S# SC) S# AND C#=‘C2’ORDER BY S.S# G: SELECT S.S#，SNAME FROM S
- 查询选修了课程号为“C1”的学生的姓名和年龄，若用下列SQL的SELECT语句表达时，错误的是( )。 A: SELECT SNAME，AGE FROM S WHERE B: S#=(SELECT S C: S#FROM SC WHERE D: C#='C1') E: SELECT SNAME，AGE FROM S，SC WHERE F: S#=S G: S# AND S H: C#='C1' I: SELECT SNAME，AGE FROM S，SC WHERE J: S#=S K: S# AND S L: C#='C1' ORDERBY M: S# N: SELECT SNAME，AGE FROM S WHERE O: S#=(SELECT S P: S# FROM SC WHERE S Q: C#='C1')
- 有关系S(S#，SNAME，SAGE)，C(C#，CNAME)，SC(S#，C#，GRADE)。若要查找分数(grade)不及格的学生姓名(sname)，则以上正确的有？（ ） A: SELECT sname FROM s, sc WHERE grade<60 B: SELECT sname FROM s WHERE sno IN(SELECT Cno FROM sc WHERE grade<60) C: SELECT sname FROM s, sc WHERE s.sno=sc.sno AND grade<60 D: SELECT sname FROM s, sc WHERE s.sno=sc.sno OR grade<60
- 有关系S(S#，SNAME，SAGE)，C(C#，CNAME)，SC(S#，C#，GRADE)。若要查找分数(grade)不及格的学生姓名(sname)，则以上正确的有？（ ） A: SELECT sname FROM s, sc WHERE grade<60 B: SELECT sname FROM s WHERE sno IN(SELECT Cno FROM sc WHERE grade<60) C: SELECT sname FROM s, sc WHERE s.sno=sc.sno AND grade<60 D: SELECT sname FROM s, sc WHERE s.sno=sc.sno OR grade<60
内容
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有学生表S(S#,SN,SEX,AGE,DEPT),课程表C(C#,CN),学生选课表SC(S#,C#,GRADE),检索选修课程"C2"的学生中成绩最高的学生的学号,正确的SELECT语句是_________。 A: SELECT S# FROM SCWHERE C#="C2" AND GRADE>=(SELECT GRADE FROM SC WHERE C#="C2") B: SELECT S# FROM SCWHERE C#="C2" AND GRADE IN(SELECT GRADE FROM SC WHERE C#="C2") C: SELECT S# FROM SCWHERE C#="C2" AND GRADE NOT IN(SELECT GRADE FROM SC WHERE C#="C2") D: SELECT S# FROM SCWHERE C#="C2" AND GRADE>=ALL
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检索选修课程号为“D3”的学生中成绩最高的学生的学号，正确的、SELECT语句是______ A: SELECT S# B: FROM SC C: WHERE C#='D3'AND GRADE＞= D: (SELECT GRADE FROM SC E: WHERE C#='D3')； F: SELECT S# G: FROM SC H: WHERE C#='D3'AND GRADE IN I: (SELECT GRADE FROM SC J: WHERE C#='D3')； K: SELECT S# L: FROM SC M: WHERE C#='D3'AND GRADE NOT IN N: (SELECT GRADE FROM SC O: WHERE C#='D3')； P: SELECT S# Q: FROM SC R: WHERE C#='D3'AND GRADE＞=ALL S: (SELECT GRADE FROM SC T: WHERE C#='D3')；
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有关系S(S#，SNAME，SEX)，C(C#，CNAME)，SC(S#，C#)。其中S#为学生号，SNAME为学生姓名，SEX为性别，C#为课程号，CNAME为课程名。要查询选修“网络技术”课的全体男学生姓名的SQL语句是SELECT SNAME FROM S，C，SC WHERE ( )。 A: S#=SC.S# AND SEX=′男′AND CNAME=′网络技术′ B: S#=SC.S# AND C.C#=SC.C# AND CNAME=′网络技术′ C: S#=SC.S# AND C.C#=SC．C# AND D: SEX=′女′AND CNAME=′网络技术′
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查询选修了课程号为“C2”的学生号和姓名，若用下列SQL的SELECT语句表达时，（）是错误的。 A: SELECT S.S#，SNAME FROM S WHERE S.S# B: =(SELECT SC.S#FROM SC WHERE C#='C2') C: SELECT S.S#，SNAME FROM S，SC D: WHERE S.S#=SC.S# AND C#='C2' E: SELECT S.S#，SNAME FROM S，SC F: WHERE S.S#=SC.S# AND C#='C2' ORDER BY S.S# G: SELEC S.S#，SNAME FROM S WHERE S.S# H: IN(SELECT SC.S# FROM SC WHERE C#='C2')
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假设数据库中有“学生(S)－选课(SC)－课程(C)”的三个关系：S（S#，SNAME，SEX，AGE） SC（S#，C#，GRADE） C（C#，CNAME，TEACHER） 若要求查找姓“王”的学生的学号和姓名。下面列出的 SQL 语句中正确的是______。Ⅰ.SELECT S#,SNAME FROM S WHERE SNAME=’王%’ Ⅱ.SELECT S#,SNAME FROM S WHERE SNAME LIKE ’王%’Ⅲ.SELECT S#,SNAME FROM S WHERE SNAME LIKE ’王＿%’ A: Ⅰ B: Ⅱ C: Ⅲ D: 全部