针对学生选课表sc（sno, cno, grade），其中sno为学号，cno为课程号，grade为成绩。以下（）语句可查询选修了两门以上成绩在90分以上课程的学生学号。
A: select snofrom scwhere grade>;90group by snohaving count(cno)>;2
B: select snofrom scwhere grade>;90group by snohaving count(*)>;2
C: select snofrom scwhere grade>;90 and count(*)>;2group by sno
D: select snofrom scwhere grade>;90group by snohaving count(distinct sno)>;2
A: select snofrom scwhere grade>;90group by snohaving count(cno)>;2
B: select snofrom scwhere grade>;90group by snohaving count(*)>;2
C: select snofrom scwhere grade>;90 and count(*)>;2group by sno
D: select snofrom scwhere grade>;90group by snohaving count(distinct sno)>;2
举一反三
- 针对学生选课表sc（sno, cno, grade），其中sno为学号，cno为课程号，grade为成绩。以下（ ）语句可查询选修了两门以上成绩在90分以上课程的学生学号。 A: select sno from scwhere grade>90group by snohaving count(cno)>2 B: select sno from scwhere grade>90group by snohaving count(*)>2 C: select sno from scwhere grade>90 and count(*)>2group by sno D: select sno from scwhere grade>90group by snohaving count(sno)>2
- 针对学生选课表sc（sno, cno, grade），其中sno为学号，cno为课程号，grade为成绩。以下（ ）语句可查询选修了两门以上成绩在90分以上课程的学生学号。 A: select sno from sc where grade>90 group by sno having count(cno)>2; B: select sno from sc where grade>90 group by sno having count(*)>2; C: select sno from sc where grade>90 and count(*)>2 group by sno; D: select sno from sc where grade>90 group by sno having count(sno)>2;
- 以下（ ）语句可查询选修了三门以上成绩在80分以上课程的学生学号。 A: select sno from scwhere grade>80group by snohaving count(cno)>3 B: select sno from scwhere grade>80group by snohaving count(*)>3 C: select sno from scwhere grade>80 and count(*)>3group by sno D: select sno from scwhere grade>80group by snohaving count(sno)>3
- 下列SQL语句中，_____________可以在“学生-课程”数据库正确实现“查询选修并成绩良好3门以上课程的学生学号及其满足条件的课程门数”。 A: SELECT Sno，COUNT(*)FROM SCGROUP BY SnoHAVING Grade>=80 AND COUNT(*) >3 B: SELECT Sno，COUNT(*)FROM SCWHERE Grade>=80GROUP BY SnoHAVING COUNT(*) >3 C: SELECT Sno，COUNT(*)FROM SCGROUP BY SnoWHERE Grade>=80HAVING COUNT(*) >3 D: SELECT Sno，COUNT(*)FROM SCGROUP BY SnoWHERE Grade>=80 AND HAVING COUNT(*) >3
- 针对S_T数据库，查询既选修了1号课程又选修3号课程的学生学号，以下不正确的SQL命令是（ ）。 A: select snofrom scwhere cno='1' and cno='3' B: select snofrom scwhere cno='1'intersectselect snofrom scwhere cno='3' C: select snofrom scwhere cno='1' and sno in(select snofrom scwhere cno='3') D: select a.snofrom sc a,sc bwhere a.sno=b.sno and a.cno='1' and b.cno='3'