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
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 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
- 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
- 针对表SC（sno, cno, grade），其中sno为学号，cno为课程号，grade为成绩。以下哪个操作（ ）统计出每位学生所选课程的最高分和最低分。 A: select sno,max(grade), min(grade) from sc B: select sno,max(grade), min(grade) from sc order by sno C: select sno,max(grade), min(grade) from sc group by sno D: select sno,avg(grade), sum(grade) from sc group by sno
内容
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表sc中存放了多个学生的多门课程的成绩，sno为学号，cno为课程号，grade为成绩。要查询平均分最高的学生学号和平均分，下列（）语句可以实现。 A: SELECT top 1 sno,avg(grade) FROM sc group by sno order by avg(grade) desc B: SELECT sno,max(avg(grade)) FROM sc group by sno C: SELECT sno,max(grade), avg(grade) FROM sc group by sno D: SELECT sno,max(grade) FROM sc group by sno
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关系SC(Sno，Cno，Grade)表示学号，课程号，成绩。现要查询最高分在91分以上的学生的学号和平均成绩，正确的语句是______。 A: SELECT Sno，MAX(Grade) FROM SC WHERE MAX(Grade)＞=91 GROUP BY Sno B: SELECT Sno，MAX(Grade) FROM SC GROUP RY Sno HAVING MAX(Grade)＞=91 C: SELECT Sno，MAX(Grade) FROM SC WHERE MAX(Grade)＞=91 ORDER BY Sno D: SELECT Sno，MAX(Grade) FROM SC GROUP BY Cno HAVING MAX(Grade)＞=91
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关系SC(Sno，Cno，Grade)表示学号，课程号，成绩。现要查询平均分在90分以上的学生的学号和平均成绩，正确的语句是______。 A: SELECT Sno，AVG(Grad FROM SC WHERE AVG(Grad＞=90 GROUP BY Sno B: SELECT Sno，AVG(Grad FROM SC GROUP BY Sno HAVING AVG(Grad＞=90 C: SELECT Sno，AVG(Grad FROM SC WHERE AVG(Grad＞=90 ORDER BY Sno D: SELECT Sno，AVG(Grad FROM SC GROUP BY Cno HAVING AVG(Grad＞=90
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关系SC(Sno，Cno，Grade)表示学号、课程号、成绩。现要查询最高分在91分以上的学生的学号和平均成绩，正确的语句是______。 A: SELECT Sno，MAX(Grade)<br> FROM SC<br> WHERE MAX(Grade)≥91<br> GROUP BY Sno B: SELECT Sno，MAX(Grade)<br> FROM SC<br> GROUP BY Sno<br> HAVING MAX(Grade)≥91 C: SELECT Sno，MAX(Grade)<br> FROM SC<br> WHERE MAX(Grade)≥91<br> ORDER BY Sno D: SELECT Sno，MAX(Grade)<br> FROM SC<br> GROUP BY Cno<br> HAVING MAX(Grade)≥91
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查询所有有成绩的学生学号和课程号。正确的SELECT语句是（）。 A: Select sno , cno from sc where grade < > null B: Select sno as 学号, cno as 课程号 from sc where grade is not null C: Select sno , cno from sc where grade !=‘ ’ D: Select sno , cno from sc where grade is not null