学生成绩表中成绩列（Grade）为空可以表示为Grade=NULL。
学生成绩表中成绩列（Grade）为空可以表示为Grade=NULL。
相关考题：
第（37）-（38）题基于学生-课程数据库中的三个基本表： 学生信息表：s（sno, sname, sex, age, dept） 主码为sno 课程信息表：c（cno, cname, teacher） 主码为cno 学生选课信息表：sc（sno, cno, grade） 主码为（sno, cno） \从学生选课信息表中找出无成绩的元组\的SQL语句是A．SELECT * FROM sc WHERE grade=NULLB．SELECT * FROM sc WHERE grade IS ' 'C．SELECT * FROM sc WHERE grade IS NULLD．SELECT * FROM sc WHERE grade =' '
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(Grade) FROM SC WHERE AVG(Grade)＞=90 GROUP BY SnoB．SELECT Sno，AVG(Grade) FROM SC GROUP BY Sno HAVING AVG(Grade)＞=90C．SELECT Sno，AVG(Grade) FROM SC WHERE AVG(Grade)＞=90 ORDER BY SnoD．SELECT Sno，AVG(Grade) FROM SC GROUP BY Cno HAVING AVG(Grade)＞=90
假定有三个关系，学生关系S、课程关系C和学生选课关系SC，它们的结构如下： S(S#，SN，Sex，Age，Dept)，C(C#，CN)，SC(S#，C#，Grade)。其中，S#为学生号，SN为姓名，Sex为性别，Age为年龄，Dept为系别，C#为课程号，CN为课程名，Grade为成绩。检索选修课程“C2”的学生中成绩最高的学生的学号，正确的SQL．语句是______。A．SELECT S#FROM SC WHERE C#="C2" AND Grade IN (SELECT Grade FROM SC WHERE C#="C2")B．SELECT S# FROM SC WHERE C#="C2" AND Grade＞= (SELECT Grade FROM SC WHERE C#="C2")C．SELECT S# FROM SC WHERE C#="C2" AND Grade＞=ALL (SELECT Grade FROM SC WHERE C#="C2")D．SELECT S# FROM SC WHERE C#="C2" AND Gtade NOT IN (SELECT Grade FROM SC WHERE C#="C2")
基于学生．课程数据库中的三个基本表：学生信息表：s (snumber, sname, sex, age, dept)主码为snumber课程信息表：c(cnumber, cname,teacher)主码为cnumber学生选课信息表：sc(snumber, cnumber, grade)主码为(snumber, cnumber)“从学生选课信息表中找出无成绩的元组”的SQL语句是（ ）。A)SELECT ﹡FROM sc WHERE grade=NULLB)SELECT﹡FROM sc WHERE grade IS "C)SELECT﹡FROM sc WHERE grade IS NULLD)SELECT﹡FROM sc WHERE grade=''
根据上题，除了上述的2张表，还包括一张成绩表SC,成绩表SC包括学生编号Sno，课程编号Cn。和成绩Grade，其中Grade为数值型(带小数)。请按下列要求，完成查询语句。(1)找出所有姓刘的老师讲授的课程的课程号和课程名(2)找出“数据库应用”课程成绩在90分以上的学生的姓名
设有如下关系： SC(sno，cname，grade)(各属性含义分别为学生的学号、课程名称、成绩)现要将所 有学生的课程成绩增加10分，以下能正确地完成此操作的SQL命令是( )。A．MODIFY sc SET grade+10B．UPDATE sc SET grade+10C．MODIFY sc SET grade=grade+10D．UPDATE sc SET grade=grade+10
设有一成绩关系SC(Sno，Cno，Grade)，其中的属性分别表示学号、课程号、成绩。为了查询课程髓的最高分和最低分之差，可以使用语句： SELECT(24)FROM SC WHERE Gno=‘C1’A．MAX-MIN(Grade)B．(Grade)MAX-MINC．MAX(Grade)-MIN(Grade)D．MAX-MIN
设关系模式SCG (S#, C#, grade)中S#为学生学号，C#为课程号，grade为某学号学生学某号课程的考试成绩。今要查询每门课程的平均成绩，且要求查询的结果按平均成绩升序排列，平均成绩相同时，按课程号降序排列，则用SQL查询语言应为(1)。若查询的结果仅限于平均分数超过80分的，则应(2)。A．Select C#，AVG(grade) From SCG Group by grade Order by 2，C# DescB．Select C#，AVG(grade) From SCG Group by C# Order by 2，C# DescC．Select C#，AVG(grade) From SCG Where C#，AVG Desc Group by gradeD．Select C#，AVG(grade) From SCG Group by AVG(grade) Order by 2，C# Desc
要从学生成绩表(Stu_grade)中按课程号(Cno)统计出每门课程的选修人数，(27)可以实现这一功能。Stu_ gradeA．select Cno，count(stu_no)from Stu_grade group by CnoB．select Cno，count (stu_ no)from Stu_ gradeC．select Cno from Stu_gradeD．select Cno from Stu_grade group by Cno
对于数据表：student(sno,sname,sex,age,grade)，查询学习成绩为空的学生的学号和姓名，下面语句正确的是______。A．SELECT sno,sname FROM student WHERE gade=NULLB．SELECT sno,sname FROM student WHERE grade IS NULLC．SELECT sno,age FROM student WHERE grade IS NULLD．SELECT mo,age FROM student WHERE grade=NULL
要从学生成绩表(stu_ grade)中查询出学号(stu_ no)等于109的学生姓名(name)和成绩(grade)，(13)可以实现这一功能。A．select *from stu_ gradeB．select* from stu_ grade where stu_ no='109'C．select name, grade from stu_ gradeD．select name，grade from stu_ grade where stu_ no='109'
对于学生信息表：student(sno，sname，sex，age，grade)，查询学习成绩为空的学生的学号和姓名，下面语句正确的是A．SELECT sno，sname FROM student WHERE grade=NULLB．SELECT sno，sname FROM student WHERE grade IS NULLC．SELECT sno，age FROM student WHERE grade IS NULLD．SELECT sno，age FROM student WHERE grade=NULL
设在SQL Server 2008某数据库中有表SC（Sn0，Cn0，Grade），其中Grade列的类型为int。若在查询成绩时，希望将成绩按“优”、“良”、“中”、“及格”和“不及格”形式显示，则下列Case函数中正确的是（ ）。A.Case GradeWhen Grade between 90 and 100 THEN Grade=ˊ优ˊWhen Grade between 80 and 89 THEN Grade=ˊ良ˊWhen Grade between 70 and 79 THEN Grade=ˊ由ˊWhen Grade between 60 and 69 THEN Grade=ˊ及格ˊElse Grade=ˊ不及格ˊEndB.Case GradeWhen Grade between 90 and 100 THEN ˊ优ˊWhen Grade between 80 and 89 THEN ˊ良ˊWhen Grade between 70 and 79 THENˊ中ˊWhen Grade between 60 and 69 THENˊ及格ˊElseˊ不及格ˊEndC.CaseWhen Grade between 90 and 100 THEN Grade=ˊ优ˊWhen Grade between 80 and 89 THEN Grade=ˊ良ˊWhen Grade between 70 and 79 THEN Grade=ˊ由ˊWhen Grade between 60 and 69 THEN Grade=ˊ及格ˊElse Grade=ˊ不及格ˊEndD.CaseWhen Grade between 90 and 100 THENˊ优ˊWhen Grade between 80 and 89 THEN ˊ良ˊWhen Grade between 70 and 79 THEN ˊ由ˊWhen Grade between 60 and 69 THEN ˊ及格ˊElseˊ不及格ˊEnd
从学生选课信息表中找出无成绩的元组的SQL语句是( )。A．SELECT*FROM sc WHERE grade＝NULLB．SELECT*FROM sc WHERE grade IS"C．SELECT*FROM sc WHERE grade IS NULLD．SELECT*FROM sc WHERE grade="
设有如下关系 SC(sno，cname，grade)(各属性含义分别为学生的学号、课程名称、成绩)现要将所有学 生的课程成绩增加10分，以下能正确地完成此操作的SQL命令是A． MODIFYScSET grade+10B．UPDATEScSET grade+10C．MODIFYScSET grade=grade+10D．UPDATEScSET grade=grade+10
成绩表grade中字段score代表分数，以下()语句返回成绩表中的最低分。A.selectmax(score)fromgradeB.Selectrrun(score)fromgradeC.selecttop1scorefromgradeorderbyscoreascD.selecttop1scorefromgradeorderbyscoredesc
设SC表中记录成绩的列为：Grade，类型为int。若在查询成绩时，希望将成绩按‘优’、‘良’、‘中’、‘及格’和‘不及格’形式显示，正确的Case函数是（）。A Case Grade When 90~100 THEN ’优’ When 80~89 THEN ’良’ When 70~79 THEN ’中’ When 60~69 THEN ’及格’ Else ’不及格’ EndB Case When Grade between 90 and 100 THEN Grade = ’优’ When Grade between 80 and 89 THEN Grade = ’良’ When Grade between 70 and 79 THEN Grade = ’中’ When Grade between 60 and 69 THEN Grade = ’及格’ Else Grade = ’不及格’ EndC Case When Grade between 90 and 100 THEN ’优’ When Grade between 80 and 89 THEN ’良’ When Grade between 70 and 79 THEN ’中’ When Grade between 60 and 69 THEN ’及格’ Else ’不及格’ EndDCase Grade When 90~100 THEN Grade = ’优’ When 80~89 THEN Grade = ’良’ When 70~79 THEN Grade = ’中’ When 60~69 THEN Grade = ’及格’ Else Grade = ’不及格’ End
成绩表grade中字段score代表分数，以下（）语句返回成绩表中的最低分。（选择两项）A、select max(score) from gradeB、select top 1 score from grade order by score ascC、Select min(score) from gradeD、select top 1 score from grade order by score desc
设在某SELECT语句的WHERE子句中，需要对Grade列的空值进行处理。下列关于空值的操作，错误的是（）。A、Grade IS NOT NULLB、Grade IS NULLC、Grade = NULLD、NOT （Grade IS NULL）
学生成绩表grade中有字段score（float），现在要把所有在55分至60之间的分数提高5分，以下sql语句正确的是（）A、Update grade set score=score+5B、Update grade set score=score+5 where score=55 or score =60C、Update grade set score=score+5 where score between 55 and 60D、Update grade set score=score+5 where score =55 and score =60
学生选课信息表：sc（sno，cno，grade），主键为（sno，cno），从学生选课信息表中找出无成绩的元组的SQL语句是（）。A、SELECT * FROM sc WHERE grade=NULLB、SELECT * FROM sc WHERE grade IS“ ”C、SELECT * FROM sc WHERE grade=‘ ’D、SELECT * FROM sc WHERE grade IS NULL
成绩表grade中字段st_id代表学号，score代表分数，以下（）语句返回成绩表中的最低分。A、SELECT max(score) FROM gradeB、SELECT TOP 1 score FROM grade ORDERBY score ASCC、SELECT st_id，MIN(score) FROM gradeD、SELECT TOP 1 score FROM grade ORDERBY score DESC
单选题学生成绩表grade中有字段score（float），现在要把所有在55至60分之间的分数提高5分，以下SQL语句正确的是（）。AUpdate grade set score=score+5 where score in 55..60BUpdate grade set score=score+5 where score =55 AND score =60CUpdate grade set score=score+5 where score between 55 or 60DUpdate grade set score=score+5 where score =55 and score =60
多选题成绩表grade中字段score代表分数，以下（）语句返回成绩表中的最低分。Aselect max(score) from gradeBselect top 1 score from grade order by score ascCSelect min(score) from gradeDselect top 1 score from grade order by score desc
多选题成绩表grade中字段score代表分数，以下（）语句返回成绩表中的最低分。Aselect max（score）from gradeBselect top1score from grade order by score ascCSelect min（score）fromgradeDselect top1score from grade order by score desc
单选题设SC表中记录成绩的列为：Grade，类型为int。若在查询成绩时，希望将成绩按‘优’、‘良’、‘中’、‘及格’和‘不及格’形式显示，正确的Case函数是（）。A Case Grade When 90~100 THEN ’优’ When 80~89 THEN ’良’ When 70~79 THEN ’中’ When 60~69 THEN ’及格’ Else ’不及格’ EndB Case When Grade between 90 and 100 THEN Grade = ’优’ When Grade between 80 and 89 THEN Grade = ’良’ When Grade between 70 and 79 THEN Grade = ’中’ When Grade between 60 and 69 THEN Grade = ’及格’ Else Grade = ’不及格’ EndC Case When Grade between 90 and 100 THEN ’优’ When Grade between 80 and 89 THEN ’良’ When Grade between 70 and 79 THEN ’中’ When Grade between 60 and 69 THEN ’及格’ Else ’不及格’ EndDCase Grade When 90~100 THEN Grade = ’优’ When 80~89 THEN Grade = ’良’ When 70~79 THEN Grade = ’中’ When 60~69 THEN Grade = ’及格’ Else Grade = ’不及格’ End
判断题学生成绩表中成绩列（Grade）为空可以表示为Grade=NULL。A对B错