50條SQL查詢技巧、查詢語句示例
更新時(shí)間：2015年06月16日 11:27:32 投稿：junjie
這篇文章主要介紹了50條SQL查詢技巧、查詢語句示例,本文以學(xué)生表、課程表、成績(jī)表、教師表為例,講解不同需求下的SQL語句寫法,需要的朋友可以參考下
Student(S#,Sname,Sage,Ssex) 學(xué)生表
Course(C#,Cname,T#) 課程表
SC(S#,C#,score) 成績(jī)表
Teacher(T#,Tname) 教師表
問題：
1、查詢“001”課程比“002”課程成績(jī)高的所有學(xué)生的學(xué)號(hào)；
復(fù)制代碼 代碼如下:
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、查詢平均成績(jī)大于60分的同學(xué)的學(xué)號(hào)和平均成績(jī)；
復(fù)制代碼 代碼如下:
select S#,avg(score)
from sc
group by S# having avg(score) >60;
3、查詢所有同學(xué)的學(xué)號(hào)、姓名、選課數(shù)、總成績(jī)；
復(fù)制代碼 代碼如下:
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、查詢姓“李”的老師的個(gè)數(shù)；
復(fù)制代碼 代碼如下:
select count(distinct(Tname))
from Teacher
where Tname like '李%';
5、查詢沒學(xué)過“葉平”老師課的同學(xué)的學(xué)號(hào)、姓名；
復(fù)制代碼 代碼如下:
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='葉平');
6、查詢學(xué)過“001”并且也學(xué)過編號(hào)“002”課程的同學(xué)的學(xué)號(hào)、姓名；
復(fù)制代碼 代碼如下:
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、查詢學(xué)過“葉平”老師所教的所有課的同學(xué)的學(xué)號(hào)、姓名；
復(fù)制代碼 代碼如下:
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='葉平' group by S# having count(SC.C#)=(select count(C#) from Course,Teacher where Teacher.T#=Course.T# and Tname='葉平'));
8、查詢課程編號(hào)“002”的成績(jī)比課程編號(hào)“001”課程低的所有同學(xué)的學(xué)號(hào)、姓名；
復(fù)制代碼 代碼如下:
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、查詢所有課程成績(jī)小于60分的同學(xué)的學(xué)號(hào)、姓名；
復(fù)制代碼 代碼如下:
select S#,Sname
from Student
where S# not in (select Student.S# from Student,SC where S.S#=SC.S# and score>60);
10、查詢沒有學(xué)全所有課的同學(xué)的學(xué)號(hào)、姓名；
復(fù)制代碼 代碼如下:
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、查詢至少有一門課與學(xué)號(hào)為“1001”的同學(xué)所學(xué)相同的同學(xué)的學(xué)號(hào)和姓名；
復(fù)制代碼 代碼如下:
select S#,Sname from Student,SC where Student.S#=SC.S# and C# in select C# from SC where S#='1001';
12、查詢至少學(xué)過學(xué)號(hào)為“001”同學(xué)所有一門課的其他同學(xué)學(xué)號(hào)和姓名；
復(fù)制代碼 代碼如下:
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“葉平”老師教的課的成績(jī)都更改為此課程的平均成績(jī)；
復(fù)制代碼 代碼如下:
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='葉平');
14、查詢和“1002”號(hào)的同學(xué)學(xué)習(xí)的課程完全相同的其他同學(xué)學(xué)號(hào)和姓名；
復(fù)制代碼 代碼如下:
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、刪除學(xué)習(xí)“葉平”老師課的SC表記錄；
復(fù)制代碼 代碼如下:
Delect SC
from course ,Teacher
where Course.C#=SC.C# and Course.T#= Teacher.T# and Tname='葉平';
16、向SC表中插入一些記錄，這些記錄要求符合以下條件：沒有上過編號(hào)“003”課程的同學(xué)學(xué)號(hào)、2、
號(hào)課的平均成績(jī)；
復(fù)制代碼 代碼如下:
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、按平均成績(jī)從高到低顯示所有學(xué)生的“數(shù)據(jù)庫”、“企業(yè)管理”、“英語”三門的課程成績(jī)，按如下形式顯示： 學(xué)生ID,,數(shù)據(jù)庫,企業(yè)管理,英語,有效課程數(shù),有效平均分
復(fù)制代碼 代碼如下:
SELECT S# as 學(xué)生ID
,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='004') AS 數(shù)據(jù)庫
,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='001') AS 企業(yè)管理
,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='006') AS 英語
,COUNT(*) AS 有效課程數(shù), AVG(t.score) AS 平均成績(jī)
FROM SC AS t
GROUP BY S#
ORDER BY avg(t.score)
18、查詢各科成績(jī)最高和最低的分：以如下形式顯示：課程ID，最高分，最低分
復(fù)制代碼 代碼如下:
SELECT L.C# As 課程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、按各科平均成績(jī)從低到高和及格率的百分?jǐn)?shù)從高到低順序
復(fù)制代碼 代碼如下:
SELECT t.C# AS 課程號(hào),max(course.Cname)AS 課程名,isnull(AVG(score),0) AS 平均成績(jī)
,100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分?jǐn)?shù)
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、查詢?nèi)缦抡n程平均成績(jī)和及格率的百分?jǐn)?shù)(用"1行"顯示): 企業(yè)管理（001），馬克思（002），OO&UML （003），數(shù)據(jù)庫（004）
復(fù)制代碼 代碼如下:
SELECT SUM(CASE WHEN C# ='001' THEN score ELSE 0 END)/SUM(CASE C# WHEN '001' THEN 1 ELSE 0 END) AS 企業(yè)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 企業(yè)管理及格百分?jǐn)?shù)
,SUM(CASE WHEN C# = '002' THEN score ELSE 0 END)/SUM(CASE C# WHEN '002' THEN 1 ELSE 0 END) AS 馬克思平均分
,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 馬克思及格百分?jǐn)?shù)
,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?jǐn)?shù)
,SUM(CASE WHEN C# = '004' THEN score ELSE 0 END)/SUM(CASE C# WHEN '004' THEN 1 ELSE 0 END) AS 數(shù)據(jù)庫平均分
,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 數(shù)據(jù)庫及格百分?jǐn)?shù)
FROM SC
21、查詢不同老師所教不同課程平均分從高到低顯示
復(fù)制代碼 代碼如下:
SELECT max(Z.T#) AS 教師ID,MAX(Z.Tname) AS 教師姓名,C.C# AS 課程ＩＤ,MAX(C.Cname) AS 課程名稱,AVG(Score) AS 平均成績(jī)
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、查詢?nèi)缦抡n程成績(jī)第 3 名到第 6 名的學(xué)生成績(jī)單：企業(yè)管理（001），馬克思（002），UML （003），數(shù)據(jù)庫（004）
[學(xué)生ID],[學(xué)生姓名],企業(yè)管理,馬克思,UML,數(shù)據(jù)庫,平均成績(jī)
復(fù)制代碼 代碼如下:
SELECT DISTINCT top 3
SC.S# As 學(xué)生學(xué)號(hào),
Student.Sname AS 學(xué)生姓名 ,
T1.score AS 企業(yè)管理,
T2.score AS 馬克思,
T3.score AS UML,
T4.score AS 數(shù)據(jù)庫,
ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) as 總分
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、統(tǒng)計(jì)列印各科成績(jī),各分?jǐn)?shù)段人數(shù):課程ID,課程名稱,[100-85],[85-70],[70-60],[ <60]
復(fù)制代碼 代碼如下:
SELECT SC.C# as 課程ID, Cname as 課程名稱
,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、查詢學(xué)生平均成績(jī)及其名次
復(fù)制代碼 代碼如下:
SELECT 1+(SELECT COUNT( distinct 平均成績(jī))
FROM (SELECT S#,AVG(score) AS 平均成績(jī)
FROM SC
GROUP BY S#
) AS T1
WHERE 平均成績(jī) > T2.平均成績(jī)) as 名次,
S# as 學(xué)生學(xué)號(hào),平均成績(jī)
FROM (SELECT S#,AVG(score) 平均成績(jī)
FROM SC
GROUP BY S#
) AS T2
ORDER BY 平均成績(jī) desc;
25、查詢各科成績(jī)前三名的記錄:(不考慮成績(jī)并列情況)
復(fù)制代碼 代碼如下:
SELECT t1.S# as 學(xué)生ID,t1.C# as 課程ID,Score as 分?jǐn)?shù)
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、查詢每門課程被選修的學(xué)生數(shù)
復(fù)制代碼 代碼如下:
select c#,count(S#) from sc group by C#;
27、查詢出只選修了一門課程的全部學(xué)生的學(xué)號(hào)和姓名
復(fù)制代碼 代碼如下:
select SC.S#,Student.Sname,count(C#) AS 選課數(shù)
from SC ,Student
where SC.S#=Student.S# group by SC.S# ,Student.Sname having count(C#)=1;
28、查詢男生、女生人數(shù)
復(fù)制代碼 代碼如下:
Select count(Ssex) as 男生人數(shù) from Student group by Ssex having Ssex='男';
Select count(Ssex) as 女生人數(shù) from Student group by Ssex having Ssex='女'；
29、查詢姓“張”的學(xué)生名單
復(fù)制代碼 代碼如下:
SELECT Sname FROM Student WHERE Sname like '張%';
30、查詢同名同性學(xué)生名單，并統(tǒng)計(jì)同名人數(shù)
復(fù)制代碼 代碼如下:
select Sname,count(*) from Student group by Sname having count(*)>1;
31、1981年出生的學(xué)生名單(注：Student表中Sage列的類型是datetime)
復(fù)制代碼 代碼如下:
select Sname, CONVERT(char (11),DATEPART(year,Sage)) as age
from student
where CONVERT(char(11),DATEPART(year,Sage))='1981';
32、查詢每門課程的平均成績(jī)，結(jié)果按平均成績(jī)升序排列，平均成績(jī)相同時(shí)，按課程號(hào)降序排列
復(fù)制代碼 代碼如下:
Select C#,Avg(score) from SC group by C# order by Avg(score),C# DESC ;
33、查詢平均成績(jī)大于85的所有學(xué)生的學(xué)號(hào)、姓名和平均成績(jī)
復(fù)制代碼 代碼如下:
select Sname,SC.S# ,avg(score)
from Student,SC
where Student.S#=SC.S# group by SC.S#,Sname having avg(score)>85;
34、查詢課程名稱為“數(shù)據(jù)庫”，且分?jǐn)?shù)低于60的學(xué)生姓名和分?jǐn)?shù)
復(fù)制代碼 代碼如下:
Select Sname,isnull(score,0)
from Student,SC,Course
where SC.S#=Student.S# and SC.C#=Course.C# and Course.Cname='數(shù)據(jù)庫'and score <60;
35、查詢所有學(xué)生的選課情況；
復(fù)制代碼 代碼如下:
SELECT SC.S#,SC.C#,Sname,Cname
FROM SC,Student,Course
where SC.S#=Student.S# and SC.C#=Course.C# ;
36、查詢?nèi)魏我婚T課程成績(jī)?cè)?0分以上的姓名、課程名稱和分?jǐn)?shù)；
復(fù)制代碼 代碼如下:
SELECT distinct student.S#,student.Sname,SC.C#,SC.score
FROM student,Sc
WHERE SC.score>=70 AND SC.S#=student.S#;
37、查詢不及格的課程，并按課程號(hào)從大到小排列
復(fù)制代碼 代碼如下:
select c# from sc where scor e <60 order by C# ;
38、查詢課程編號(hào)為003且課程成績(jī)?cè)?0分以上的學(xué)生的學(xué)號(hào)和姓名；
復(fù)制代碼 代碼如下:
select SC.S#,Student.Sname from SC,Student where SC.S#=Student.S# and Score>80 and C#='003';
39、求選了課程的學(xué)生人數(shù)
復(fù)制代碼 代碼如下:
select count(*) from sc;
40、查詢選修“葉平”老師所授課程的學(xué)生中，成績(jī)最高的學(xué)生姓名及其成績(jī)
復(fù)制代碼 代碼如下:
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='葉平' and SC.score=(select max(score)from SC where C#=C.C# );
41、查詢各個(gè)課程及相應(yīng)的選修人數(shù)
復(fù)制代碼 代碼如下:
select count(*) from sc group by C#;
42、查詢不同課程成績(jī)相同的學(xué)生的學(xué)號(hào)、課程號(hào)、學(xué)生成績(jī)
復(fù)制代碼 代碼如下:
select distinct A.S#,B.score from SC A ,SC B where A.Score=B.Score and A.C# <>B.C# ;
43、查詢每門功成績(jī)最好的前兩名
復(fù)制代碼 代碼如下:
SELECT t1.S# as 學(xué)生ID,t1.C# as 課程ID,Score as 分?jǐn)?shù)
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、統(tǒng)計(jì)每門課程的學(xué)生選修人數(shù)（超過10人的課程才統(tǒng)計(jì)）。要求輸出課程號(hào)和選修人數(shù)，查詢結(jié)果按人數(shù)降序排列，查詢結(jié)果按人數(shù)降序排列，若人數(shù)相同，按課程號(hào)升序排列
復(fù)制代碼 代碼如下:
select C# as 課程號(hào),count(*) as 人數(shù)
from sc
group by C#
order by count(*) desc,c#
45、檢索至少選修兩門課程的學(xué)生學(xué)號(hào)
復(fù)制代碼 代碼如下:
select S#
from sc
group by s#
having count(*) > = 2
46、查詢?nèi)繉W(xué)生都選修的課程的課程號(hào)和課程名
復(fù)制代碼 代碼如下:
select C#,Cname
from Course
where C# in (select c# from sc group by c#)
47、查詢沒學(xué)過“葉平”老師講授的任一門課程的學(xué)生姓名
復(fù)制代碼 代碼如下:
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='葉平');
48、查詢兩門以上不及格課程的同學(xué)的學(xué)號(hào)及其平均成績(jī)
復(fù)制代碼 代碼如下:
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、檢索“004”課程分?jǐn)?shù)小于60，按分?jǐn)?shù)降序排列的同學(xué)學(xué)號(hào)
復(fù)制代碼 代碼如下:
select S# from SC where C#='004'and score <60 order by score desc;
50、刪除“002”同學(xué)的“001”課程的成績(jī)
復(fù)制代碼 代碼如下:
delete from Sc where S#='001'and C#='001';
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