举一反三
- 【单选题】5. 假定student表中有字段grade,grade代表分数,依次统计grade字段的最大值,最小值,平均值的SQL语句是 A. SELECT max(grade),min(grade),average(grade) FROM student; B. SELECT max(grade),min(grade),avg(grade) FROM student; C. SELECT min(grade),average(grade),max(grade) FROM student; D. SELECT min(grade),avg(grade),max(grade) FROM student;
- 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
- 已知关系模式：sc(sno,sname,grade)，各属性含义依次为学号、课程名、分数。要查找“数据库”课分数最高的学生的学号，正确的SQL语句是 A: SELECT sno FROM sc WHERE sname = "数据库" AND grade = MAX(grade) B: SELECT sno FROM sc FOR sname = "数据库" OR grade＞=MAX(grade) C: SELECT sno FROM sc WHERE sname = "数据库" AND grade = (SELECT MAX(grade) FROM sc) D: SELECT sno FROM sc FOR sname = "数据库" OR grade = (SELECT MAX(grade) FROM sc)
- 已知关系模式：SC(sno,sname,grade)，各属性含义依次为学号、课程名、分数。要查找“数据库”课分数最高的学生的学号，正确的SQL语句是( )。 A: SELECT sno FROM sc WHERE sname="数据库"AND grade=MAX(grade) B: SELECT sno FROM sc FOR sname="数据库"OR grade＞=MAX(grade) C: SELECT sno FROM sc WHERE sname="数据库"AND grade=(SELECT MAX(grade)FROM sc) D: SELECT sno FROM sc FOR sname="数据库"OR grade=(SELECT MAX(grade)FROM s
- 查询平均成绩小于70分的学生学号和平均成绩 A: SELECT Sno, AVG(grade) FROM SC GROUPBYSno B: SELECT Sno, AVG(grade) FROM SC GROUPBYSno HAVINGAVG(grade)<70; C: SELECT Sno, grade FROM SC GROUPBYSno HAVINGAVG(grade)<70;
内容
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按照课程号进行分组，统计学生平均成绩大于60分的学生的信息( ) A: select cid,avg(grade) from sc group by cid having avg(grade)>60 B: select cid,avg(grade) from student group by cid having avg(grade)>60 C: select cid,avg(grade) from course where avg(grade)>60 group by cid D: select cid,avg(grade) from student where avg(grade)>60 group by cid
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按照学号进行分组，统计学生的平均成绩，且平均分按降序排列 A: select sid, avg(grade) from sc group by sid order by avg(grade) desc B: select sid, avg(grade) from sc group by cid order by avg(grade) desc C: select sid, avg(grade) from student group by sid order by avg(grade) desc D: select sid, avg(grade) from student group by cid order by avg(grade)
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统计学生成绩中的最高分，下列语句正确的是 A: SELECT AVG(grade) FROM student; B: SELECT (SUM(grade) / Count(id)) FROM student; C: SELECT MAX(grade) FROM student; D: SELECT MIN(grade) FROM student;
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已知关系模式：sc(sno，sname，grade)，各属性含义依次为学号、课程名、分数。要查找“数据库”课分数最高的学生的学号，正确的SQL语句是（）。 A: SELECT sno FROM SC. WHERE sname="数据库"AND. grade=MAX(grade) B: SELECT sno FROM SC. FOR sname="数据库"OR grade＞MAX(grade) C: SELECT sno FROM SC. WHERE shame="数据库"AND. grade=(SELECT MAX(grade)FROM sc) D: SELECT son FROM SC. FOR sname="数据库"OR grade=(SELECT MAX(grade. FROM sc)
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检索选修了课程”C1”的学生中成绩最高的学生的学号，正确的SELECT语句为（ ） A: SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE >=ALL (SELECT Grade FROM SC WHERE Cno=’C1’); B: SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE IN (SELECT Grade FROM SC WHERE Cno=’C1’); C: SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE > ANY (SELECT Grade FROM SC WHERE Cno=’C1’); D: SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE >= (SELECT Grade FROM SC WHERE Cno=’C1’);