一个项目涉及到的50个Sql语句(整理版)

/* 标题：一个项目涉及到的50个Sql语句(整理版) 作者：爱新觉罗.毓华(十八年风雨，守得冰山雪莲花开) 时间：2010-05-10 地点：重庆航天职业学院 说明：以下五十个语句都按照测试数据进行过测试，最好每次只单独运行一个语句。 问题及描述： --1.学生表 Student(S#,Sname,Sage,Ssex) --S# 学生编号,Sname 学生姓名,Sage 出生年月,Ssex 学生性别 --2.课程表 Course(C#,Cname,T#) --C# --课程编号,Cname 课程名称,T# 教师编号 --3.教师表 Teacher(T#,Tname) --T# 教师编号,Tname 教师姓名 --4.成绩表 SC(S#,C#,score) --S# 学生编号,C# 课程编号,score 分数 */ --创建测试数据 create table Student(S# varchar(10),Sname nvarchar(10),Sage datetime,Ssex nvarchar(10)) insert into Student values('01' , N'赵雷' , '1990-01-01' , N'男') insert into Student values('02' , N'钱电' , '1990-12-21' , N'男') insert into Student values('03' , N'孙风' , '1990-05-20' , N'男') insert into Student values('04' , N'李云' , '1990-08-06' , N'男') insert into Student values('05' , N'周梅' , '1991-12-01' , N'女') insert into Student values('06' , N'吴兰' , '1992-03-01' , N'女') insert into Student values('07' , N'郑竹' , '1989-07-01' , N'女') insert into Student values('08' , N'王菊' , '1990-01-20' , N'女') create table Course(C# varchar(10),Cname nvarchar(10),T# varchar(10)) insert into Course values('01' , N'语文' , '02') insert into Course values('02' , N'数学' , '01') insert into Course values('03' , N'英语' , '03') create table Teacher(T# varchar(10),Tname nvarchar(10)) insert into Teacher values('01' , N'张三') insert into Teacher values('02' , N'李四') insert into Teacher values('03' , N'王五') create table SC(S# varchar(10),C# varchar(10),score decimal(18,1)) insert into SC values('01' , '01' , 80) insert into SC values('01' , '02' , 90) insert into SC values('01' , '03' , 99) insert into SC values('02' , '01' , 70) insert into SC values('02' , '02' , 60) insert into SC values('02' , '03' , 80) insert into SC values('03' , '01' , 80) insert into SC values('03' , '02' , 80) insert into SC values('03' , '03' , 80) insert into SC values('04' , '01' , 50) insert into SC values('04' , '02' , 30) insert into SC values('04' , '03' , 20) insert into SC values('05' , '01' , 76) insert into SC values('05' , '02' , 87) insert into SC values('06' , '01' , 31) insert into SC values('06' , '03' , 34) insert into SC values('07' , '02' , 89) insert into SC values('07' , '03' , 98) go --1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数 --1.1、查询同时存在"01"课程和"02"课程的情况 select a.* , b.score [课程'01'的分数],c.score [课程'02'的分数] from Student a , SC b , SC c where a.S# = b.S# and a.S# = c.S# and b.C# = '01' and c.C# = '02' and b.score > c.score --1.2、查询同时存在"01"课程和"02"课程的情况和存在"01"课程但可能不存在"02"课程的情况(不存在时显示为null)(以下存在相同内容时不再解释) select a.* , b.score [课程"01"的分数],c.score [课程"02"的分数] from Student a left join SC b on a.S# = b.S# and b.C# = '01' left join SC c on a.S# = c.S# and c.C# = '02' where b.score > isnull(c.score,0) --2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数 --2.1、查询同时存在"01"课程和"02"课程的情况 select a.* , b.score [课程'01'的分数],c.score [课程'02'的分数] from Student a , SC b , SC c where a.S# = b.S# and a.S# = c.S# and b.C# = '01' and c.C# = '02' and b.score < c.score --2.2、查询同时存在"01"课程和"02"课程的情况和不存在"01"课程但存在"02"课程的情况 select a.* , b.score [课程"01"的分数],c.score [课程"02"的分数] from Student a left join SC b on a.S# = b.S# and b.C# = '01' left join SC c on a.S# = c.S# and c.C# = '02' where isnull(b.score,0) < c.score --3、查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩 select a.S# , a.Sname , cast(avg(b.score) as decimal(18,2)) avg_score from Student a , sc b where a.S# = b.S# group by a.S# , a.Sname having cast(avg(b.score) as decimal(18,2)) >= 60 order by a.S# --4、查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩 --4.1、查询在sc表存在成绩的学生信息的SQL语句。 select a.S# , a.Sname , cast(avg(b.score) as decimal(18,2)) avg_score from Student a , sc b where a.S# = b.S# group by a.S# , a.Sname having cast(avg(b.score) as decimal(18,2)) < 60 order by a.S# --4.2、查询在sc表中不存在成绩的学生信息的SQL语句。 select a.S# , a.Sname , isnull(cast(avg(b.score) as decimal(18,2)),0) avg_score from Student a left join sc b on a.S# = b.S# group by a.S# , a.Sname having isnull(cast(avg(b.score) as decimal(18,2)),0) < 60 order by a.S# --5、查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩 --5.1、查询所有有成绩的SQL。 select a.S# [学生编号], a.Sname [学生姓名], count(b.C#) 选课总数, sum(score) [所有课程的总成绩] from Student a , SC b where a.S# = b.S# group by a.S#,a.Sname order by a.S# --5.2、查询所有(包括有成绩和无成绩)的SQL。 select a.S# [学生编号], a.Sname [学生姓名], count(b.C#) 选课总数, sum(score) [所有课程的总成绩] from Student a left join SC b on a.S# = b.S# group by a.S#,a.Sname order by a.S# --6、查询"李"姓老师的数量 --方法1 select count(Tname) ["李"姓老师的数量] from Teacher where Tname like N'李%' --方法2 select count(Tname) ["李"姓老师的数量] from Teacher where left(Tname,1) = N'李' /* "李"姓老师的数量 ----------- 1 */ --7、查询学过"张三"老师授课的同学的信息 select distinct Student.* from Student , SC , Course , Teacher where Student.S# = SC.S# and SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = N'张三' order by Student.S# --8、查询没学过"张三"老师授课的同学的信息 select m.* from Student m where S# not in (select distinct SC.S# from SC , Course , Teacher where SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = N'张三') order by m.S# --9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息 --方法1 select Student.* from Student , SC where Student.S# = SC.S# and SC.C# = '01' and exists (Select 1 from SC SC_2 where SC_2.S# = SC.S# and SC_2.C# = '02') order by Student.S# --方法2 select Student.* from Student , SC where Student.S# = SC.S# and SC.C# = '02' and exists (Select 1 from SC SC_2 where SC_2.S# = SC.S# and SC_2.C# = '01') order by Student.S# --方法3 select m.* from Student m where S# in ( select S# from ( select distinct S# from SC where C# = '01' union all select distinct S# from SC where C# = '02' ) t group by S# having count(1) = 2 ) order by m.S# --10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息 --方法1 select Student.* from Student , SC where Student.S# = SC.S# and SC.C# = '01' and not exists (Select 1 from SC SC_2 where SC_2.S# = SC.S# and SC_2.C# = '02') order by Student.S# --方法2 select Student.* from Student , SC where Student.S# = SC.S# and SC.C# = '01' and Student.S# not in (Select SC_2.S# from SC SC_2 where SC_2.S# = SC.S# and SC_2.C# = '02') order by Student.S# --11、查询没有学全所有课程的同学的信息 --11.1、 select Student.* from Student , SC where Student.S# = SC.S# group by Student.S# , Student.Sname , Student.Sage , Student.Ssex having count(C#) < (select count(C#) from Course) --11.2 select Student.* from Student left join SC on Student.S# = SC.S# group by Student.S# , Student.Sname , Student.Sage , Student.Ssex having count(C#) < (select count(C#) from Course) --12、查询至少有一门课与学号为"01"的同学所学相同的同学的信息 select distinct Student.* from Student , SC where Student.S# = SC.S# and SC.C# in (select C# from SC where S# = '01') and Student.S# <> '01' --13、查询和"01"号的同学学习的课程完全相同的其他同学的信息 select Student.* from Student where S# in (select distinct SC.S# from SC where S# <> '01' and SC.C# in (select distinct C# from SC where S# = '01') group by SC.S# having count(1) = (select count(1) from SC where S#='01')) --14、查询没学过"张三"老师讲授的任一门课程的学生姓名 select student.* from student where student.S# not in (select distinct sc.S# from sc , course , teacher where sc.C# = course.C# and course.T# = teacher.T# and teacher.tname = N'张三') order by student.S# --15、查询两门及其以上不及格课程的同学的学号，姓名及其平均成绩 select student.S# , student.sname , cast(avg(score) as decimal(18,2)) avg_score from student , sc where student.S# = SC.S# and student.S# in (select S# from SC where score < 60 group by S# having count(1) >= 2) group by student.S# , student.sname --16、检索"01"课程分数小于60，按分数降序排列的学生信息 select student.* , sc.C# , sc.score from student , sc where student.S# = SC.S# and sc.score < 60 and sc.C# = '01' order by sc.score desc --17、按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩 --17.1 SQL 2000 静态 select a.S# 学生编号 , a.Sname 学生姓名 , max(case c.Cname when N'语文' then b.score else null end) [语文], max(case c.Cname when N'数学' then b.score else null end) [数学], max(case c.Cname when N'英语' then b.score else null end) [英语], cast(avg(b.score) as decimal(18,2)) 平均分 from Student a left join SC b on a.S# = b.S# left join Course c on b.C# = c.C# group by a.S# , a.Sname order by 平均分 desc --17.2 SQL 2000 动态 declare @sql nvarchar(4000) set @sql = 'select a.S# ' + N'学生编号' + ' , a.Sname ' + N'学生姓名' select @sql = @sql + ',max(case c.Cname when N'''+Cname+''' then b.score else null end) ['+Cname+']' from (select distinct Cname from Course) as t set @sql = @sql + ' , cast(avg(b.score) as decimal(18,2)) ' + N'平均分' + ' from Student a left join SC b on a.S# = b.S# left join Course c on b.C# = c.C# group by a.S# , a.Sname order by ' + N'平均分' + ' desc' exec(@sql) --17.3 有关sql 2005的动静态写法参见我的文章《普通行列转换(version 2.0)》或《普通行列转换(version 3.0)》。 --18、查询各科成绩最高分、最低分和平均分：以如下形式显示：课程ID，课程name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率 --及格为>=60，中等为：70-80，优良为：80-90，优秀为：>=90 --方法1 select m.C# [课程编号], m.Cname [课程名称], max(n.score) [最高分], min(n.score) [最低分], cast(avg(n.score) as decimal(18,2)) [平均分], cast((select count(1) from SC where C# = m.C# and score >= 60)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [及格率(%)], cast((select count(1) from SC where C# = m.C# and score >= 70 and score < 80 )*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [中等率(%)], cast((select count(1) from SC where C# = m.C# and score >= 80 and score < 90 )*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [优良率(%)], cast((select count(1) from SC where C# = m.C# and score >= 90)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [优秀率(%)] from Course m , SC n where m.C# = n.C# group by m.C# , m.Cname order by m.C# --方法2 select m.C# [课程编号], m.Cname [课程名称], (select max(score) from SC where C# = m.C#) [最高分], (select min(score) from SC where C# = m.C#) [最低分], (select cast(avg(score) as decimal(18,2)) from SC where C# = m.C#) [平均分], cast((select count(1) from SC where C# = m.C# and score >= 60)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [及格率(%)], cast((select count(1) from SC where C# = m.C# and score >= 70 and score < 80 )*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [中等率(%)], cast((select count(1) from SC where C# = m.C# and score >= 80 and score < 90 )*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [优良率(%)], cast((select count(1) from SC where C# = m.C# and score >= 90)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [优秀率(%)] from Course m order by m.C# --19、按各科成绩进行排序，并显示排名 --19.1 sql 2000用子查询完成 --Score重复时保留名次空缺 select t.* , px = (select count(1) from SC where C# = t.C# and score > t.score) + 1 from sc t order by t.c# , px --Score重复时合并名次 select t.* , px = (select count(distinct score) from SC where C# = t.C# and score >= t.score) from sc t order by t.c# , px --19.2 sql 2005用rank,DENSE_RANK完成 --Score重复时保留名次空缺(rank完成) select t.* , px = rank() over(partition by c# order by score desc) from sc t order by t.C# , px --Score重复时合并名次(DENSE_RANK完成) select t.* , px = DENSE_RANK() over(partition by c# order by score desc) from sc t order by t.C# , px --20、查询学生的总成绩并进行排名 --20.1 查询学生的总成绩 select m.S# [学生编号] , m.Sname [学生姓名] , isnull(sum(score),0) [总成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname order by [总成绩] desc --20.2 查询学生的总成绩并进行排名，sql 2000用子查询完成，分总分重复时保留名次空缺和不保留名次空缺两种。 select t1.* , px = (select count(1) from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(sum(score),0) [总成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t2 where 总成绩 > t1.总成绩) + 1 from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(sum(score),0) [总成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t1 order by px select t1.* , px = (select count(distinct 总成绩) from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(sum(score),0) [总成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t2 where 总成绩 >= t1.总成绩) from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(sum(score),0) [总成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t1 order by px --20.3 查询学生的总成绩并进行排名，sql 2005用rank,DENSE_RANK完成，分总分重复时保留名次空缺和不保留名次空缺两种。 select t.* , px = rank() over(order by [总成绩] desc) from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(sum(score),0) [总成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t order by px select t.* , px = DENSE_RANK() over(order by [总成绩] desc) from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(sum(score),0) [总成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t order by px --21、查询不同老师所教不同课程平均分从高到低显示 select m.T# , m.Tname , cast(avg(o.score) as decimal(18,2)) avg_score from Teacher m , Course n , SC o where m.T# = n.T# and n.C# = o.C# group by m.T# , m.Tname order by avg_score desc --22、查询所有课程的成绩第2名到第3名的学生信息及该课程成绩 --22.1 sql 2000用子查询完成 --Score重复时保留名次空缺 select * from (select t.* , px = (select count(1) from SC where C# = t.C# and score > t.score) + 1 from sc t) m where px between 2 and 3 order by m.c# , m.px --Score重复时合并名次 select * from (select t.* , px = (select count(distinct score) from SC where C# = t.C# and score >= t.score) from sc t) m where px between 2 and 3 order by m.c# , m.px --22.2 sql 2005用rank,DENSE_RANK完成 --Score重复时保留名次空缺(rank完成) select * from (select t.* , px = rank() over(partition by c# order by score desc) from sc t) m where px between 2 and 3 order by m.C# , m.px --Score重复时合并名次(DENSE_RANK完成) select * from (select t.* , px = DENSE_RANK() over(partition by c# order by score desc) from sc t) m where px between 2 and 3 order by m.C# , m.px --23、统计各科成绩各分数段人数：课程编号,课程名称,[100-85],[85-70],[70-60],[0-60]及所占百分比 --23.1 统计各科成绩各分数段人数：课程编号,课程名称,[100-85],[85-70],[70-60],[0-60] --横向显示 select Course.C# [课程编号] , Cname as [课程名称] , sum(case when score >= 85 then 1 else 0 end) [85-100], sum(case when score >= 70 and score < 85 then 1 else 0 end) [70-85], sum(case when score >= 60 and score < 70 then 1 else 0 end) [60-70], sum(case when score < 60 then 1 else 0 end) [0-60] from sc , Course where SC.C# = Course.C# group by Course.C# , Course.Cname order by Course.C# --纵向显示1(显示存在的分数段) select m.C# [课程编号] , m.Cname [课程名称] , 分数段 = ( case when n.score >= 85 then '85-100' when n.score >= 70 and n.score < 85 then '70-85' when n.score >= 60 and n.score < 70 then '60-70' else '0-60' end) , count(1) 数量 from Course m , sc n where m.C# = n.C# group by m.C# , m.Cname , ( case when n.score >= 85 then '85-100' when n.score >= 70 and n.score < 85 then '70-85' when n.score >= 60 and n.score < 70 then '60-70' else '0-60' end) order by m.C# , m.Cname , 分数段 --纵向显示2(显示存在的分数段，不存在的分数段用0显示) select m.C# [课程编号] , m.Cname [课程名称] , 分数段 = ( case when n.score >= 85 then '85-100' when n.score >= 70 and n.score < 85 then '70-85' when n.score >= 60 and n.score < 70 then '60-70' else '0-60' end) , count(1) 数量 from Course m , sc n where m.C# = n.C# group by all m.C# , m.Cname , ( case when n.score >= 85 then '85-100' when n.score >= 70 and n.score < 85 then '70-85' when n.score >= 60 and n.score < 70 then '60-70' else '0-60' end) order by m.C# , m.Cname , 分数段 --23.2 统计各科成绩各分数段人数：课程编号,课程名称,[100-85],[85-70],[70-60],[<60]及所占百分比 --横向显示 select m.C# 课程编号, m.Cname 课程名称, (select count(1) from SC where C# = m.C# and score < 60) [0-60], cast((select count(1) from SC where C# = m.C# and score < 60)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [百分比(%)], (select count(1) from SC where C# = m.C# and score >= 60 and score < 70) [60-70], cast((select count(1) from SC where C# = m.C# and score >= 60 and score < 70)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [百分比(%)], (select count(1) from SC where C# = m.C# and score >= 70 and score < 85) [70-85], cast((select count(1) from SC where C# = m.C# and score >= 70 and score < 85)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [百分比(%)], (select count(1) from SC where C# = m.C# and score >= 85) [85-100], cast((select count(1) from SC where C# = m.C# and score >= 85)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [百分比(%)] from Course m order by m.C# --纵向显示1(显示存在的分数段) select m.C# [课程编号] , m.Cname [课程名称] , 分数段 = ( case when n.score >= 85 then '85-100' when n.score >= 70 and n.score < 85 then '70-85' when n.score >= 60 and n.score < 70 then '60-70' else '0-60' end) , count(1) 数量 , cast(count(1) * 100.0 / (select count(1) from sc where C# = m.C#) as decimal(18,2)) [百分比(%)] from Course m , sc n where m.C# = n.C# group by m.C# , m.Cname , ( case when n.score >= 85 then '85-100' when n.score >= 70 and n.score < 85 then '70-85' when n.score >= 60 and n.score < 70 then '60-70' else '0-60' end) order by m.C# , m.Cname , 分数段 --纵向显示2(显示存在的分数段，不存在的分数段用0显示) select m.C# [课程编号] , m.Cname [课程名称] , 分数段 = ( case when n.score >= 85 then '85-100' when n.score >= 70 and n.score < 85 then '70-85' when n.score >= 60 and n.score < 70 then '60-70' else '0-60' end) , count(1) 数量 , cast(count(1) * 100.0 / (select count(1) from sc where C# = m.C#) as decimal(18,2)) [百分比(%)] from Course m , sc n where m.C# = n.C# group by all m.C# , m.Cname , ( case when n.score >= 85 then '85-100' when n.score >= 70 and n.score < 85 then '70-85' when n.score >= 60 and n.score < 70 then '60-70' else '0-60' end) order by m.C# , m.Cname , 分数段 --24、查询学生平均成绩及其名次 --24.1 查询学生的平均成绩并进行排名，sql 2000用子查询完成，分平均成绩重复时保留名次空缺和不保留名次空缺两种。 select t1.* , px = (select count(1) from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t2 where 平均成绩 > t1.平均成绩) + 1 from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t1 order by px select t1.* , px = (select count(distinct 平均成绩) from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t2 where 平均成绩 >= t1.平均成绩) from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t1 order by px --24.2 查询学生的平均成绩并进行排名，sql 2005用rank,DENSE_RANK完成，分平均成绩重复时保留名次空缺和不保留名次空缺两种。 select t.* , px = rank() over(order by [平均成绩] desc) from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t order by px select t.* , px = DENSE_RANK() over(order by [平均成绩] desc) from ( select m.S# [学生编号] , m.Sname [学生姓名] , isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] from Student m left join SC n on m.S# = n.S# group by m.S# , m.Sname ) t order by px --25、查询各科成绩前三名的记录 --25.1 分数重复时保留名次空缺 select m.* , n.C# , n.score from Student m, SC n where m.S# = n.S# and n.score in (select top 3 score from sc where C# = n.C# order by score desc) order by n.C# , n.score desc --25.2 分数重复时不保留名次空缺，合并名次 --sql 2000用子查询实现 select * from (select t.* , px = (select count(distinct score) from SC where C# = t.C# and score >= t.score) from sc t) m where px between 1 and 3 order by m.c# , m.px --sql 2005用DENSE_RANK实现 select * from (select t.* , px = DENSE_RANK() over(partition by c# order by score desc) from sc t) m where px between 1 and 3 order by m.C# , m.px --26、查询每门课程被选修的学生数 select c# , count(S#)[学生数] from sc group by C# --27、查询出只有两门课程的全部学生的学号和姓名 select Student.S# , Student.Sname from Student , SC where Student.S# = SC.S# group by Student.S# , Student.Sname having count(SC.C#) = 2 order by Student.S# --28、查询男生、女生人数 select count(Ssex) as 男生人数 from Student where Ssex = N'男' select count(Ssex) as 女生人数 from Student where Ssex = N'女' select sum(case when Ssex = N'男' then 1 else 0 end) [男生人数],sum(case when Ssex = N'女' then 1 else 0 end) [女生人数] from student select case when Ssex = N'男' then N'男生人数' else N'女生人数' end [男女情况] , count(1) [人数] from student group by case when Ssex = N'男' then N'男生人数' else N'女生人数' end --29、查询名字中含有"风"字的学生信息 select * from student where sname like N'%风%' select * from student where charindex(N'风' , sname) > 0 --30、查询同名同性学生名单，并统计同名人数 select Sname [学生姓名], count(*) [人数] from Student group by Sname having count(*) > 1 --31、查询1990年出生的学生名单(注：Student表中Sage列的类型是datetime) select * from Student where year(sage) = 1990 select * from Student where datediff(yy,sage,'1990-01-01') = 0 select * from Student where datepart(yy,sage) = 1990 select * from Student where convert(varchar(4),sage,120) = '1990' --32、查询每门课程的平均成绩，结果按平均成绩降序排列，平均成绩相同时，按课程编号升序排列 select m.C# , m.Cname , cast(avg(n.score) as decimal(18,2)) avg_score from Course m, SC n where m.C# = n.C# group by m.C# , m.Cname order by avg_score desc, m.C# asc --33、查询平均成绩大于等于85的所有学生的学号、姓名和平均成绩 select a.S# , a.Sname , cast(avg(b.score) as decimal(18,2)) avg_score from Student a , sc b where a.S# = b.S# group by a.S# , a.Sname having cast(avg(b.score) as decimal(18,2)) >= 85 order by a.S# --34、查询课程名称为"数学"，且分数低于60的学生姓名和分数 select sname , score from Student , SC , Course where SC.S# = Student.S# and SC.C# = Course.C# and Course.Cname = N'数学' and score < 60 --35、查询所有学生的课程及分数情况； select Student.* , Course.Cname , SC.C# , SC.score from Student, SC , Course where Student.S# = SC.S# and SC.C# = Course.C# order by Student.S# , SC.C# --36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数； select Student.* , Course.Cname , SC.C# , SC.score from Student, SC , Course where Student.S# = SC.S# and SC.C# = Course.C# and SC.score >= 70 order by Student.S# , SC.C# --37、查询不及格的课程 select Student.* , Course.Cname , SC.C# , SC.score from Student, SC , Course where Student.S# = SC.S# and SC.C# = Course.C# and SC.score < 60 order by Student.S# , SC.C# --38、查询课程编号为01且课程成绩在80分以上的学生的学号和姓名； select Student.* , Course.Cname , SC.C# , SC.score from Student, SC , Course where Student.S# = SC.S# and SC.C# = Course.C# and SC.C# = '01' and SC.score >= 80 order by Student.S# , SC.C# --39、求每门课程的学生人数 select Course.C# , Course.Cname , count(*) [学生人数] from Course , SC where Course.C# = SC.C# group by Course.C# , Course.Cname order by Course.C# , Course.Cname --40、查询选修"张三"老师所授课程的学生中，成绩最高的学生信息及其成绩 --40.1 当最高分只有一个时 select top 1 Student.* , Course.Cname , SC.C# , SC.score from Student, SC , Course , Teacher where Student.S# = SC.S# and SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = N'张三' order by SC.score desc --40.2 当最高分出现多个时 select Student.* , Course.Cname , SC.C# , SC.score from Student, SC , Course , Teacher where Student.S# = SC.S# and SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = N'张三' and SC.score = (select max(SC.score) from SC , Course , Teacher where SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = N'张三') --41、查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩 --方法1 select m.* from SC m ,(select C# , score from SC group by C# , score having count(1) > 1) n where m.C#= n.C# and m.score = n.score order by m.C# , m.score , m.S# --方法2 select m.* from SC m where exists (select 1 from (select C# , score from SC group by C# , score having count(1) > 1) n where m.C#= n.C# and m.score = n.score) order by m.C# , m.score , m.S# --42、查询每门功成绩最好的前两名 select t.* from sc t where score in (select top 2 score from sc where C# = T.C# order by score desc) order by t.C# , t.score desc --43、统计每门课程的学生选修人数（超过5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，若人数相同，按课程号升序排列 select Course.C# , Course.Cname , count(*) [学生人数] from Course , SC where Course.C# = SC.C# group by Course.C# , Course.Cname having count(*) >= 5 order by [学生人数] desc , Course.C# --44、检索至少选修两门课程的学生学号 select student.S# , student.Sname from student , SC where student.S# = SC.S# group by student.S# , student.Sname having count(1) >= 2 order by student.S# --45、查询选修了全部课程的学生信息 --方法1 根据数量来完成 select student.* from student where S# in (select S# from sc group by S# having count(1) = (select count(1) from course)) --方法2 使用双重否定来完成 select t.* from student t where t.S# not in ( select distinct m.S# from ( select S# , C# from student , course ) m where not exists (select 1 from sc n where n.S# = m.S# and n.C# = m.C#) ) --方法3 使用双重否定来完成 select t.* from student t where not exists(select 1 from ( select distinct m.S# from ( select S# , C# from student , course ) m where not exists (select 1 from sc n where n.S# = m.S# and n.C# = m.C#) ) k where k.S# = t.S# ) --46、查询各学生的年龄 --46.1 只按照年份来算 select * , datediff(yy , sage , getdate()) [年龄] from student --46.2 按照出生日期来算，当前月日 < 出生年月的月日则，年龄减一 select * , case when right(convert(varchar(10),getdate(),120),5) < right(convert(varchar(10),sage,120),5) then datediff(yy , sage , getdate()) - 1 else datediff(yy , sage , getdate()) end [年龄] from student --47、查询本周过生日的学生 select * from student where datediff(week,datename(yy,getdate()) + right(convert(varchar(10),sage,120),6),getdate()) = 0 --48、查询下周过生日的学生 select * from student where datediff(week,datename(yy,getdate()) + right(convert(varchar(10),sage,120),6),getdate()) = -1 --49、查询本月过生日的学生 select * from student where datediff(mm,datename(yy,getdate()) + right(convert(varchar(10),sage,120),6),getdate()) = 0 --50、查询下月过生日的学生 select * from student where datediff(mm,datename(yy,getdate()) + right(convert(varchar(10),sage,120),6),getdate()) = -1 drop table Student,Course,Teacher,SC