/*標題：一個項目涉及到的50個Sql語句(整理版)說明：以下五十個語句都按照測試數據進行過測試，最好每次只單獨運行一個語句。*/--1.學生表Student(S,Sname,Sage,Ssex) --S 學生編號,Sname 學生姓名,Sage 出生年月,Ssex 學生性別--2.課程表 Course(C,Cname,T) --C --課程編號,Cname 課程名稱,T 教師編號--3.教師表 Teacher(T,Tname) --T 教師編號,Tname 教師姓名--4.成績表 SC(S,C,score) --S 學生編號,C 課程編號,score 分數*/--創建測試數據create table Student(S varchar(10),Sname nvarchar(10),Sage datetime,Ssex nvarchar(10))insert into Student values('01' , N'趙雷' , '1990-01-01' , N'男')insert into Student values('02' , N'錢電' , '1990-12-21' , N'男')insert into Student values('03' , N'孫風' , '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'吳蘭' , '1992-03-01' , N'女')insert into Student values('07' , N'鄭竹' , '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'語文' , '02')insert into Course values('02' , N'數學' , '01')insert into Course values('03' , N'英語' , '03')create table Teacher(T varchar(10),Tname nvarchar(10))insert into Teacher values('01' , N'張三')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、查詢"01"課程比"02"課程成績高的學生的信息及課程分數--1.1、查詢同時存在"01"課程和"02"課程的情況select a.* , b.score [課程'01'的分數],c.score [課程'02'的分數] 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、查詢同時存在"01"課程和"02"課程的情況和存在"01"課程但可能不存在"02"課程的情況(不存在時顯示為null)(以下存在相同內容時不再解釋)select a.* , b.score [課程"01"的分數],c.score [課程"02"的分數] 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、查詢"01"課程比"02"課程成績低的學生的信息及課程分數--2.1、查詢同時存在"01"課程和"02"課程的情況select a.* , b.score [課程'01'的分數],c.score [課程'02'的分數] 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、查詢同時存在"01"課程和"02"課程的情況和不存在"01"課程但存在"02"課程的情況select a.* , b.score [課程"01"的分數],c.score [課程"02"的分數] 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、查詢平均成績大于等于60分的同學的學生編號和學生姓名和平均成績select a.S , a.Sname , cast(avg(b.score) as decimal(18,2)) avg_scorefrom Student a , sc bwhere a.S = b.Sgroup by a.S , a.Snamehaving cast(avg(b.score) as decimal(18,2)) >= 60 order by a.S

--4、查詢平均成績小于60分的同學的學生編號和學生姓名和平均成績--4.1、查詢在sc表存在成績的學生信息的SQL語句。select a.S , a.Sname , cast(avg(b.score) as decimal(18,2)) avg_scorefrom Student a , sc bwhere a.S = b.Sgroup by a.S , a.Snamehaving cast(avg(b.score) as decimal(18,2)) < 60 order by a.S--4.2、查詢在sc表中不存在成績的學生信息的SQL語句。select a.S , a.Sname , isnull(cast(avg(b.score) as decimal(18,2)),0) avg_scorefrom Student a left join sc bon a.S = b.Sgroup by a.S , a.Snamehaving isnull(cast(avg(b.score) as decimal(18,2)),0) < 60 order by a.S

--5、查詢所有同學的學生編號、學生姓名、選課總數、所有課程的總成績--5.1、查詢所有有成績的SQL。select a.S [學生編號], a.Sname [學生姓名], count(b.C) 選課總數, sum(score) [所有課程的總成績]from Student a , SC b where a.S = b.S group by a.S,a.Sname order by a.S--5.2、查詢所有(包括有成績和無成績)的SQL。select a.S [學生編號], a.Sname [學生姓名], count(b.C) 選課總數, sum(score) [所有課程的總成績]from Student a left join SC b on a.S = b.S group by a.S,a.Sname order by a.S

--6、查詢"李"姓老師的數量 --方法1select count(Tname) ["李"姓老師的數量] from Teacher where Tname like N'李%'--方法2select count(Tname) ["李"姓老師的數量] from Teacher where left(Tname,1) = N'李'/*"李"姓老師的數量 ----------- 1*/

--7、查詢學過"張三"老師授課的同學的信息 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'張三'order by Student.S

--8、查詢沒學過"張三"老師授課的同學的信息 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'張三') order by m.S

--9、查詢學過編號為"01"并且也學過編號為"02"的課程的同學的信息--方法1select 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2select 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3select 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、查詢學過編號為"01"但是沒有學過編號為"02"的課程的同學的信息--方法1select 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2select 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、查詢沒有學全所有課程的同學的信息 --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) --11.2select 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、查詢至少有一門課與學號為"01"的同學所學相同的同學的信息 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、查詢和"01"號的同學學習的課程完全相同的其他同學的信息 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、查詢沒學過"張三"老師講授的任一門課程的學生姓名 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'張三')order by student.S

--15、查詢兩門及其以上不及格課程的同學的學號，姓名及其平均成績 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、檢索"01"課程分數小于60，按分數降序排列的學生信息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、按平均成績從高到低顯示所有學生的所有課程的成績以及平均成績--17.1 SQL 2000 靜態 select a.S 學生編號 , a.Sname 學生姓名 , max(case c.Cname when N'語文' then b.score else null end) [語文], max(case c.Cname when N'數學' then b.score else null end) [數學], max(case c.Cname when N'英語' then b.score else null end) [英語], cast(avg(b.score) as decimal(18,2)) 平均分from Student a left join SC b on a.S = b.Sleft join Course c on b.C = c.Cgroup by a.S , a.Snameorder by 平均分 desc--17.2 SQL 2000 動態 declare @sql nvarchar(4000)set @sql = 'select a.S ' + N'學生編號' + ' , a.Sname ' + N'學生姓名'select @sql = @sql + ',max(case c.Cname when N'''+Cname+''' then b.score else null end) ['+Cname+']'from (select distinct Cname from Course) as tset @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.Cgroup by a.S , a.Sname order by ' + N'平均分' + ' desc'exec(@sql)--17.3 有關sql 2005的動靜態寫法參見我的文章《普通行列轉換(version 2.0)