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')

下列SQL语句中，正确的是（ ）。 A: SELECT S B: , SNAME FROM SC GROUP BY S C: SELECT S D: FROM SC GROUP BY S E: HAVING COUNT(*)>3 F: SELECT S G: ,Cname FROM SC GROUP BY S H: WHERE COUNT(*)>3 I: SELECT S J: FROM SC WHERE COUNT(*)>3 GROUP BY S

下列SQL语句中，正确的是（ ）。 A: SELECT S B: , SNAME FROM SC GROUP BY S C: D: SELECT S E: FROM SC GROUP BY S F: HAVING COUNT(*)>3 G: SELECT S H: ,Cname FROM SC GROUP BY S I: WHERE COUNT(*)>3 J: SELECT S K: FROM SC WHERE COUNT(*)>3 GROUP BY S L:

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语句为（ ）。 A: select S B: from sc where C C: =‘C2’and grade>= (select grade from sc where C D: =‘C2’) E: select S F: from sc where C G: =‘C2’and grade in (select grade from sc where C H: =‘C2’) I: select S J: from sc where C K: =‘C2’and grade not in (select grade from sc where C L: =‘C2’) M: select S N: from sc where C O: =‘C2’and grade>=all (select grade from sc where C P: =‘C2’)

实现“查询学生及其选课情况(基于左外连接)”的SELECT语句为()。A.SELECT S.*, C.* FROM Student S JOIN SC ON S.Sno=SC.SnoB.SELECT S.*, C.* FROM Student S LEFT JOIN SC ON S.Sno=SC.SnoC.SELECT S.*, C.* FROM Student S, SC WHERE S.Sno=SC.SnoD.SELECT S.*, C.* FROM Student S OUTER JOIN SC ON S.Sno=SC.Sno

检索选修“C2”课程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 WHERE c C: =’C2’ AND grade＞＝(SELECT grade FROM sc WHERE c D: =’C2’); E: SELECT s F: FROM sc WHERE c G: =’C2’ AND grade IN(SELECT grade FROM sc WHERE c H: =’C2’); I: SELECT s J: FROM sc WHERE c K: =’C2’ AND grade NOT IN(SELECT grade FORM sc WHERE c L: =’C2’); M: SELECT s N: FROM sc WHERE c O: =’C2’ AND grade＞＝(SELECT max(grade) FROM sc WHERE c P: =’C2’);

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&lt;60 B: SELECT sname FROM s WHERE sno IN(SELECT Cno FROM sc WHERE grade&lt;60) C: SELECT sname FROM s, sc WHERE s.sno=sc.sno AND grade&lt;60 D: SELECT sname FROM s, sc WHERE s.sno=sc.sno OR grade&lt;60

假设有三个基本表：学生表S、课程表C、学生选课表SC，它们的结构如下：S（S#，SN，SEX，AGE，DEPT） C（C#，CN） 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 B: FROM SC WHERE C C: =”C2” AND GRADE>=(SELECT GRADE FROM SC WHERE C D: = “C2”) E: SELECT S F: FROM SC WHERE C G: =”C2” AND GRADE IN (SELECT GRADE FROM SC WHERE C H: = “C2”) I: SELECT S J: FROM SC WHERE C K: =”C2” AND GRADE NOT IN (SELECT GRADE FROM SC WHERE C L: = “C2”) M: SELECT S N: FROM SC WHERE C O: =”C2” AND GRADE>=ALL (SELECT GRADE FROM SC WHERE C P: = “C2”)

【单选题】检索学生姓名及其所选修课程的课程号和成绩。正确的 SELECT 语句是 A. SELECT S．SN，SC．C#，SC．GRADE FROM S WHERE S．S#=SC．S# B. SELECT S．SN，SC．C#，SC．GRADE FROM SC WHERE S．S#＝SC．GRADE C. SELECT S．SN，SC．C#，SC．GRADE FROM S，SC WHERE S ． S#=SC ． S# D. SELECT S．SN，SC．C#，SC．GRADE FROM S ． SC