学生表、课程表、 成绩表、教师表50个常用sql语句
--Student(S#,Sname,Sage,Ssex) --学生表 --Course(C#,Cname,T#) --课程表 --SC(S#,C#,score) --成绩表 --Teacher(T#,Tname) --教师表 create table Student(S# varchar(20),Sname varchar(10),Sage int,Ssex varchar(2)) --前面加一列序号: if exists(select table_name from information_schema.tables where table_name='Temp_Table') drop table Temp_Table go select 排名=identity(int,1,1),* INTO Temp_Table from Student go select * from Temp_Table go drop database [ ] --删除空的没有名字的数据库 --问题: --1、查询“”课程比“”课程成绩高的所有学生的学号; select a.S# from (select s#,score from SC where C#='001') a,(select s#,score from SC where C#='002') b where a.score>b.score and a.s#=b.s#; --2、查询平均成绩大于分的同学的学号和平均成绩; select S#,avg(score) from sc group by S# having avg(score) >60; --3、查询所有同学的学号、姓名、选课数、总成绩; select Student.S#,Student.Sname,count(SC.C#),sum(score) from Student left Outer join SC on Student.S#=SC.S# group by Student.S#,Sname --4、查询姓“李”的老师的个数; select count(distinct(Tname)) from Teacher where Tname like '李%'; --5、查询没学过“叶平”老师课的同学的学号、姓名; select Student.S#,Student.Sname from Student where S# not in (select distinct( SC.S#) from SC,Course,Teacher where SC.C#=Course.C# and Teacher.T#=Course.T# and Teacher.Tname='叶平'); --6、查询学过“”并且也学过编号“”课程的同学的学号、姓名; select Student.S#,Student.Sname from Student,SC where Student.S#=SC.S# and SC.C#='001'and exists( Select * from SC as SC_2 where SC_2.S#=SC.S# and SC_2.C#='002'); --7、查询学过“叶平”老师所教的所有课的同学的学号、姓名; select S#,Sname from Student where S# in (select S# from SC ,Course ,Teacher where SC.C#=Course.C# and Teacher.T#=Course.T# and Teacher.Tname='叶平' group by S# having count(SC.C#)=(select count(C#) from Course,Teacher where Teacher.T#=Course.T# and Tname='叶平')); --8、查询课程编号“”的成绩比课程编号“”课程低的所有同学的学号、姓名; Select S#,Sname from (select Student.S#,Student.Sname,score ,(select score from SC SC_2 where SC_2.S#=Student.S# and SC_2.C#='002') score2 from Student,SC where Student.S#=SC.S# and C#='001') S_2 where score2 <score; --9、查询所有课程成绩小于分的同学的学号、姓名; select S#,Sname from Student where S# not in (select Student.S# from Student,SC where S.S#=SC.S# and score>60); --10、查询没有学全所有课的同学的学号、姓名; select Student.S#,Student.Sname from Student,SC where Student.S#=SC.S# group by Student.S#,Student.Sname having count(C#) <(select count(C#) from Course); --11、查询至少有一门课与学号为“”的同学所学相同的同学的学号和姓名; select S#,Sname from Student,SC where Student.S#=SC.S# and C# in select C# from SC where S#='1001'; --12、查询至少学过学号为“”同学所有一门课的其他同学学号和姓名; select distinct SC.S#,Sname from Student,SC where Student.S#=SC.S# and C# in (select C# from SC where S#='001'); --13、把“SC”表中“叶平”老师教的课的成绩都更改为此课程的平均成绩; update SC set score=(select avg(SC_2.score) from SC SC_2 where SC_2.C#=SC.C# ) from Course,Teacher where Course.C#=SC.C# and Course.T#=Teacher.T# and Teacher.Tname='叶平'); --14、查询和“”号的同学学习的课程完全相同的其他同学学号和姓名; select S# from SC where C# in (select C# from SC where S#='1002') group by S# having count(*)=(select count(*) from SC where S#='1002'); --15、删除学习“叶平”老师课的SC表记录; Delect SC from course ,Teacher where Course.C#=SC.C# and Course.T#= Teacher.T# and Tname='叶平'; --16、向SC表中插入一些记录,这些记录要求符合以下条件:没有上过编号“”课程的同学学号、、 号课的平均成绩; Insert SC select S#,'002',(Select avg(score) from SC where C#='002') from Student where S# not in (Select S# from SC where C#='002'); --17、按平均成绩从高到低显示所有学生的“数据库”、“企业管理”、“英语”三门的课程成绩,按如下形式显示:学生ID,,数据库,企业管理,英语,有效课程数,有效平均分 SELECT S# as 学生ID ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='004') AS 数据库 ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='001') AS 企业管理 ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='006') AS 英语 ,COUNT(*) AS 有效课程数, AVG(t.score) AS 平均成绩 FROM SC AS t GROUP BY S# ORDER BY avg(t.score) --18、查询各科成绩最高和最低的分:以如下形式显示:课程ID,最高分,最低分 SELECT L.C# As 课程ID,L.score AS 最高分,R.score AS 最低分 FROM SC L ,SC AS R WHERE L.C# = R.C# and L.score = (SELECT MAX(IL.score) FROM SC AS IL,Student AS IM WHERE L.C# = IL.C# and IM.S#=IL.S# GROUP BY IL.C#) AND R.Score = (SELECT MIN(IR.score) FROM SC AS IR WHERE R.C# = IR.C# GROUP BY IR.C# ); --19、按各科平均成绩从低到高和及格率的百分数从高到低顺序 SELECT t.C# AS 课程号,max(course.Cname)AS 课程名,isnull(AVG(score),0) AS 平均成绩 ,100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数 FROM SC T,Course where t.C#=course.C# GROUP BY t.C# ORDER BY 100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) DESC --20、查询如下课程平均成绩和及格率的百分数(用"1行"显示): 企业管理(),马克思(),OO&UML (),数据库() SELECT SUM(CASE WHEN C# ='001' THEN score ELSE 0 END)/SUM(CASE C# WHEN '001' THEN 1 ELSE 0 END) AS 企业管理平均分 ,100 * SUM(CASE WHEN C# = '001' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '001' THEN 1 ELSE 0 END) AS 企业管理及格百分数 ,SUM(CASE WHEN C# = '002' THEN score ELSE 0 END)/SUM(CASE C# WHEN '002' THEN 1 ELSE 0 END) AS 马克思平均分 ,100 * SUM(CASE WHEN C# = '002' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '002' THEN 1 ELSE 0 END) AS 马克思及格百分数 ,SUM(CASE WHEN C# = '003' THEN score ELSE 0 END)/SUM(CASE C# WHEN '003' THEN 1 ELSE 0 END) AS UML平均分 ,100 * SUM(CASE WHEN C# = '003' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '003' THEN 1 ELSE 0 END) AS UML及格百分数 ,SUM(CASE WHEN C# = '004' THEN score ELSE 0 END)/SUM(CASE C# WHEN '004' THEN 1 ELSE 0 END) AS 数据库平均分 ,100 * SUM(CASE WHEN C# = '004' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '004' THEN 1 ELSE 0 END) AS 数据库及格百分数 FROM SC --21、查询不同老师所教不同课程平均分从高到低显示 SELECT max(Z.T#) AS 教师ID,MAX(Z.Tname) AS 教师姓名,C.C# AS 课程ID,MAX(C.Cname) AS 课程名称,AVG(Score) AS 平均成绩 FROM SC AS T,Course AS C ,Teacher AS Z where T.C#=C.C# and C.T#=Z.T# GROUP BY C.C# ORDER BY AVG(Score) DESC --22、查询如下课程成绩第名到第名的学生成绩单:企业管理(),马克思(),UML (),数据库() [学生ID],[学生姓名],企业管理,马克思,UML,数据库,平均成绩 SELECT DISTINCT top 3 SC.S# As 学生学号, Student.Sname AS 学生姓名, T1.score AS 企业管理, T2.score AS 马克思, T3.score AS UML, T4.score AS 数据库, ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) as 总分 FROM Student,SC LEFT JOIN SC AS T1 ON SC.S# = T1.S# AND T1.C# = '001' LEFT JOIN SC AS T2 ON SC.S# = T2.S# AND T2.C# = '002' LEFT JOIN SC AS T3 ON SC.S# = T3.S# AND T3.C# = '003' LEFT JOIN SC AS T4 ON SC.S# = T4.S# AND T4.C# = '004' WHERE student.S#=SC.S# and ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) NOT IN (SELECT DISTINCT TOP 15 WITH TIES ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) FROM sc LEFT JOIN sc AS T1 ON sc.S# = T1.S# AND T1.C# = 'k1' LEFT JOIN sc AS T2 ON sc.S# = T2.S# AND T2.C# = 'k2' LEFT JOIN sc AS T3 ON sc.S# = T3.S# AND T3.C# = 'k3' LEFT JOIN sc AS T4 ON sc.S# = T4.S# AND T4.C# = 'k4' ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) DESC); --23、统计列印各科成绩,各分数段人数:课程ID,课程名称,[100-85],[85-70],[70-60],[ <60] SELECT SC.C# as 课程ID, Cname as 课程名称 ,SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85] ,SUM(CASE WHEN score BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 - 70] ,SUM(CASE WHEN score BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 - 60] ,SUM(CASE WHEN score < 60 THEN 1 ELSE 0 END) AS [60 -] FROM SC,Course where SC.C#=Course.C# GROUP BY SC.C#,Cname; --24、查询学生平均成绩及其名次 SELECT 1+(SELECT COUNT( distinct 平均成绩) FROM (SELECT S#,AVG(score) AS 平均成绩 FROM SC GROUP BY S# ) AS T1 WHERE 平均成绩> T2.平均成绩) as 名次, S# as 学生学号,平均成绩 FROM (SELECT S#,AVG(score) 平均成绩 FROM SC GROUP BY S# ) AS T2 ORDER BY 平均成绩desc; --25、查询各科成绩前三名的记录:(不考虑成绩并列情况) SELECT t1.S# as 学生ID,t1.C# as 课程ID,Score as 分数 FROM SC t1 WHERE score IN (SELECT TOP 3 score FROM SC WHERE t1.C#= C# ORDER BY score DESC ) ORDER BY t1.C#; --26、查询每门课程被选修的学生数 select c#,count(S#) from sc group by C#; --27、查询出只选修了一门课程的全部学生的学号和姓名 select SC.S#,Student.Sname,count(C#) AS 选课数 from SC ,Student where SC.S#=Student.S# group by SC.S# ,Student.Sname having count(C#)=1; --28、查询男生、女生人数 Select count(Ssex) as 男生人数from Student group by Ssex having Ssex='男'; Select count(Ssex) as 女生人数from Student group by Ssex having Ssex='女'; --29、查询姓“张”的学生名单 SELECT Sname FROM Student WHERE Sname like '张%'; --30、查询同名同性学生名单,并统计同名人数 select Sname,count(*) from Student group by Sname having count(*)>1;; --31、年出生的学生名单(注:Student表中Sage列的类型是datetime) select Sname, CONVERT(char (11),DATEPART(year,Sage)) as age from student where CONVERT(char(11),DATEPART(year,Sage))='1981'; --32、查询每门课程的平均成绩,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 Select C#,Avg(score) from SC group by C# order by Avg(score),C# DESC ; --33、查询平均成绩大于的所有学生的学号、姓名和平均成绩 select Sname,SC.S# ,avg(score) from Student,SC where Student.S#=SC.S# group by SC.S#,Sname having avg(score)>85; --34、查询课程名称为“数据库”,且分数低于的学生姓名和分数 Select Sname,isnull(score,0) from Student,SC,Course where SC.S#=Student.S# and SC.C#=Course.C# and Course.Cname='数据库'and score <60; --35、查询所有学生的选课情况; SELECT SC.S#,SC.C#,Sname,Cname FROM SC,Student,Course where SC.S#=Student.S# and SC.C#=Course.C# ; --36、查询任何一门课程成绩在分以上的姓名、课程名称和分数; SELECT distinct student.S#,student.Sname,SC.C#,SC.score FROM student,Sc WHERE SC.score>=70 AND SC.S#=student.S#; --37、查询不及格的课程,并按课程号从大到小排列 select c# from sc where scor e <60 order by C# ; --38、查询课程编号为且课程成绩在分以上的学生的学号和姓名; select SC.S#,Student.Sname from SC,Student where SC.S#=Student.S# and Score>80 and C#='003'; --39、求选了课程的学生人数 select count(*) from sc; --40、查询选修“叶平”老师所授课程的学生中,成绩最高的学生姓名及其成绩 select Student.Sname,score from Student,SC,Course C,Teacher where Student.S#=SC.S# and SC.C#=C.C# and C.T#=Teacher.T# and Teacher.Tname='叶平' and SC.score=(select max(score)from SC where C#=C.C# ); --41、查询各个课程及相应的选修人数 select count(*) from sc group by C#; --42、查询不同课程成绩相同的学生的学号、课程号、学生成绩 select distinct A.S#,B.score from SC A ,SC B where A.Score=B.Score and A.C# <>B.C# ; --43、查询每门功成绩最好的前两名 SELECT t1.S# as 学生ID,t1.C# as 课程ID,Score as 分数 FROM SC t1 WHERE score IN (SELECT TOP 2 score FROM SC WHERE t1.C#= C# ORDER BY score DESC ) ORDER BY t1.C#; --44、统计每门课程的学生选修人数(超过人的课程才统计)。要求输出课程号和选修人数,查询结果按人数降序排列,查询结果按人数降序排列,若人数相同,按课程号升序排列 select C# as 课程号,count(*) as 人数 from sc group by C# order by count(*) desc,c# --45、检索至少选修两门课程的学生学号 select S# from sc group by s# having count(*) > = 2 --46、查询全部学生都选修的课程的课程号和课程名 select C#,Cname from Course where C# in (select c# from sc group by c#) --47、查询没学过“叶平”老师讲授的任一门课程的学生姓名 select Sname from Student where S# not in (select S# from Course,Teacher,SC where Course.T#=Teacher.T# and SC.C#=course.C# and Tname='叶平'); --48、查询两门以上不及格课程的同学的学号及其平均成绩 select S#,avg(isnull(score,0)) from SC where S# in (select S# from SC where score <60 group by S# having count(*)>2)group by S#; --49、检索“”课程分数小于,按分数降序排列的同学学号 select S# from SC where C#='004'and score <60 order by score desc; --50、删除“”同学的“”课程的成绩 delete from Sc where S#='001'and C#='001'; --学生表(学号、姓名、性别、年龄、所在系) --课程表(课程号、课程名、先修课号、学分) --学生选课表(学号、课程号、成绩) --1:查询全体学生的学号和姓名 --2:查询全体学生的姓名、学号和所在系 --3: 查询全体学生的详细记录 --4: 查询全体学生的姓名及其出生年份 --5:查询全体学生姓名、出生年份和所在系,要求用小写字母表示所有系名 --6:查询选修了课程的学生学号 --7:查询计算机系(IS)所有学生的名单 --8:查询所有年龄在20以下学生的姓名和年龄 --9: 查询考试成绩有不及格的学生的学号 --10: 查询年龄在20-23 (包括20和23)之间的学生的姓名、系别和年龄 --11: 查询信息系(IS)、数学系(MA)和计算机科学系(CS)学生的姓名和性别 --12: 查询学号为95001的学生的详细情况 --13: 查询所有姓林的学生的姓名、学号和性别 --14: 查询姓“欧阳”且全名为三个汉字的学生的姓名 --15:查询名字中第二个字为“燕”字的学生姓名和学号 --16:查询所有不姓“刘”的学生的姓名 --17:查询课程名为“DB_DESIGN”的课程号的学分 --18:查询缺少成绩的学生的学号和相应的课程号(成绩字段值为Null) --19: 查询所有有成绩的学生的学号和课程号 --20: 查询所有计算机系年龄在20以下的学生姓名 --21: 查询选修了3号课程的学生的学号和成绩,查询结果按分数降序排列 --22: 查询全体学生情况,查询结果按所在系的系号升序排列,同一系中的学生按年龄降序排列 --23: 查询学生总人数 --24: 查询选修了课程的学生人数 --25: 计算1号课程的学生的平均成绩 --26: 计算1号课程的学生的最高成绩分数 --27:求各个课程号及相应的选课人数 --28: 查询选修了三门以上课程的学生学号 --29:查询每个学生及其选修课情况 --30:查询每一门课的间接先行课 --31:选修2号课程且成绩在90以上的学生的学号和姓名 --32:查询每个学生的学号、姓名、选修的课程名及成绩 --33:查询与’林燕芳’在同一个系学习的学生姓名 --34: 查询其他系中比信息系某一学生小的学生姓名和年龄 --35:查询所有选修了1号课程的学生的学生姓名 --36:查询选修了全部课程的学生姓名 --37:至少选修了学生95002选修全部课程的学生号码 select Sno,Sname from Student select Sno,Sname,Sdept from Student select * from Student /*也可以逐一列出列名并用逗号分隔*/ --其中getdate是获取当前系统时间。这是一个获取到的结果 :2008-12-11 16:02:17.967 --datepart从获取到的系统时间中分离出需要的部分,这里是分离出年份,更多信息请查看SQL Server联机帮助 --下面的 出生年 指定了别名来替代原来结果页出现的文字 select Sname , (datepart( year,getdate())- Sage) '出生年' from Student --该实例利用了小写转换函数lower() 提示:通过查询分析器的 公用对象 的 字符串函数中你可以找到这个函数 select Sname '姓名' , (datepart( year,getdate())- Sage) '出生年',lower(Sdept) '所在系' from Student select Sno from sc --这里将返回全部结果,有重复的值 select distinct Sno from sc--加入关键字distinct就可以去除重复结果,只留1个 --sql 中默认对字符串大小写不敏感的,所以下面的sdept=’IS’你也可以写成sdept=’is’。如果你要启用大小写敏感,可以用下面的方法 if 敏感 select * from table where field1="AAA" COLLATE Chinese_PRC_CS_AS else select * from table where field1="AAA" COLLATE Chinese_PRC_CI_AS COLLATE 的中文排序规则参数可用下列方式查到 SELECT * FROM ::fn_helpcollations() where name like 'Chinese%' select Sname from student where sdept='IS' select Sname,Sage from student where Sage<20 select Sno from sc where grade<60 --如果要查询不在这个区间的记录,那只要改成 not between就可以了 select Sname,Sdept,Sage from student where Sage between 20 and 23 --如果要查询不属于信息系、数学系和计算机科学系的,可以在in前面加上NOT --也可以这样子写:select Sname,Ssex from student where Sdept='is' or sdept='ma' or sdept='cs' select Sname,Ssex from student where Sdept in('IS','MA','CS') --或者是select * from student where sno = '95001' select * from student where sno like '95001':--like用于字符串匹配 --百分号匹配多个字符,包括0个 select Sname,Sno,Sage from student where sname like '林%' -- 一个下划线匹配单个字符 select sname from student where sname like '欧阳_' select sname,sno from student where sname like '_燕%' select sname from student where sname not like '刘%' select Ccredit from course where cname like 'DB\_DESIGN' escape'\' --注意:这里不用使用 = null select sno,cno from sc where grade is null select sno,cno from sc where grade is not null select sname from student where sdept='CS' and sage<20 select sno,grade from sc where cno=3 order by grade desc select * from student order by sdept,sage desc select count(*) from student select count(distinct sno) from sc select avg(grade) from sc where cno='1' select max(grade) from sc where cno='1' group by 按照它后面的列值进行分组,相同的值被分在一组 select cno,count(sno) from sc group by cno --having后面的条件是根据group by 分组后的结果再进行筛选,最后只给出满足条件的分组 --where筛选的对象是整个表,而having则是分组 select sno from sc group by sno having count(sno)>=3 select a.sname,b.cno from student a ,sc b where a.sno=b.sno 或者 select a.sname,b.cno from student a left outer join sc b on a.sno=b.sno where b.cno is not null --自身连接 select a.Cno,b.Cpno from course a,course b where a.Cpno=b.Cno --31: select student.sno,student.sname from student,sc where student.sno=sc.sno and sc.cno='2' and sc.grade>=90 --32: select student.sno,student.sname,course.cname,sc.grade from (student left join sc on student.sno=sc.sno) left join course on sc.cno=course.cno --或者: --忽略cname和grade都为null的行 Select student.sno,sname,cname,grade From student,sc,course Where student.sno=sc.sno and sc.cno=course.cno --33: select sname from student where sdept=(select sdept from student where sname='林燕芳') --34: select sname,sage from student where sage<any( select sage from student where sdept='is' ) and sdept<>'IS' --35:利用 exists的查询 --exists根据是否存在行返回true/false --如果要查询没有选修1号课程的学生姓名,只要使用NOT Exists即可 select * from student where exists( select 1 from sc where student.sno=sc.sno and cno='1' ) --或者你可以使用连接查询 select * from student left join sc on student.sno=sc.sno where sc.cno='1' --36: declare @temp1 int declare @temp2 int select @temp1=count(*) from course select @temp2=sno from sc group by sno having count(sno)=@temp1 select sname from student where sno in (@temp2) --或者 --就是转换成查询没有一门课程没有选修的学生姓名 --如果把两个not都去掉就是查询所有有选修课程的学生 Select sname from student where not exists( Select 1 from course where not exists( Select 1 from sc where student.sno=sc.sno and course.cno=sc.cno ) ) --37: --同样要进行转换:查询这样的学生,没有95002选修的课程而学生X没有选修的 Select distinct sno From sc scx Where not exists ( Select 1 from sc scy Where scy.sno='95002' and not exists ( Select 1 from sc scz Where scz.sno=scx.sno and scz.cno=scy.cno ) ) and sno!='95002' --插入语句: --对每一个系求平均年龄,并把结果存入数据库 --需要创建一个表用来存储结果 Create table Deptage ( Sdept char(15), Avgage smallint ); --插入子查询结果 insert into Deptage(Sdept,Avgage) select sdept,avg(sage) from student group by sdept --查看结果 select * from deptage --修改语句; --1:将学生95001的年龄改为22岁 Update student Set sage=22 Where sno='95001'--注意如果不带where,则修改全部记录 --2:将所有的学生年龄加1岁(修改多个元组的值) Update student Set sage=sage+1; --3:将计算机系全体同学的成绩置零(带子查询的修改语句) Update sc Set grade=0 Where 'cs'=( Select sdept from student Where student.sno=sc.sno) --删除语句: --1:删除学号为95009的学生记录(删除后将无法回复) Delete from student Where sno='95009'--没有加where的话将删除该表全部记录 --2:删除计算机科学系所有学生的选课记录 Delete from sc Where 'cs'=( Select sdept From student Where student.sno=sc.sno ) --例1:查询至少选秀1号课程和3号课程号的学生号码。 --答案 select a.学号 from sc a,sc b where a.学号=b.学号 and a.课程号='1' and b.课程号='3' --例2:查询至少选修了一门直接先行课为5号课程的学生姓名。 --答案: select 姓名 from student where 学号 in( SELECT [学号] FROM [test].[dbo].[SC] where 课程号 in(SELECT 课程号 from Course where 先行课='5')) --例子3:查询选修了全部课程的学生号码和姓名。 declare @t1 int declare @t2 int select @t2=count(*) from Course select @t1=学号 from SC group by 学号 having count(学号)=@t2 --print '@t1='+cast(@t1 as varchar) Select 学号,姓名 from student where 学号=@t1 --例子4:查询信息系年龄最大的三个学生的学号及其年龄,结果按年龄降序排列。 select top 3 学号,年龄 from Student where 所在系='IS' order by 年龄 desc --例子5:查询选修了2号课程的学生名字 select 姓名 from student where 学号 in( select 学号 from sc where 课程号=2) --例子6:查询成绩为90分以上的学生名字和课程名字 select st.姓名,c.课程名 from student st left join sc s on st.学号=s.学号 left join Course c on s.课程号=c.课程号 where st.学号 in (select st.学号 from sc where s.成绩>=90) sql 取中间几条记录(select top 表达式) --查询从第M条至N条的记录,写到存储过程中就是输入参数 declare @m int-- declare @n int-- declare @x int declare @y int --设置测试值 set @m=3 set @n=10 set @x=(@n-@m+1) set @y=(@m-1) /* 语法 Select top (n-(m-1)) * from [表名] where [parimary key] not in(select top (m-1) [主键] from [表名] order by [排序字段及排序方法]) order by [排序字段及排序方法 ]; */ --测试用例,因为T-sql top 后不支持表达式,故采取下面的方法 exec('select top '+@x+'* from kf.T_Community where [C_ID] not in (select top '+@y+' [C_ID] from kf.T_Community order by [C_ID]) order by [C_ID]') --PS:如果在Orcale中,可以直接通过rownumber来控制,这样就容易多了
IT业聚集了众多世界上最聪明的人,它富有活力,充满了机遇,挑战。这就是为什么IT业如此艰难,仍然有那么多人投身于其中的原因。
posted on 2010-05-14 10:03 Timothy Yeh 阅读(6505) 评论(2) 编辑 收藏 举报