mysql基礎SQL練習
許久收藏的練習mysql語句的，現在看來任然有學習價值！
表如下：
- Student(Sid,Sname,Sage,Ssex) 學生表
- Course(Cid,Cname,Tid) 課程表
- SC(Sid,Cid,score) 成績表
- Teacher(Tid,Tname) 教師表
問題：
1、查詢“001”課程比“002”課程成績高的所有學生的學號
select a.Sid from (select sid,score from SC where Cid='001') a,(select sid,score
from
where a.score>b.score and a.sid=b.sid;
2、查詢平均成績大於60分的同學的學號和平均成績；
select Sid,avg(score)
from sc
group by Sid having avg(score) >60;
3、查詢所有同學的學號、姓名、選課數、總成績；
select Student.Sid,Student.Sname,count(SC.Cid),sum(score)
from Student left Outer join SC on Student.Sid=SC.Sid
group by Student.Sid,Sname ；
4、查詢姓“李”的老師的個數；
select
from Teacher
where Tname like '李%';
5、查詢沒學過“葉平”老師課的同學的學號、姓名；
select Student.Sid,Student.Sname
from Student
where Sid not in (select distinct( SC.Sid) from SC,Course,Teacher
where SC.Cid=Course.Cid and Teacher.Tid=Course.Tid and Teacher.Tname='葉平');
6、查詢學過“001”並且也學過編號“002”課程的同學的學號、姓名；
select Student.Sid,Student.Sname from Student,SC
where Student.Sid=SC.Sid and SC.Cid='001'and
exists( Select * from SC as SC_2 where SC_2.Sid=SC.Sid and SC_2.Cid='002');
7、查詢學過“葉平”老師所教的所有課的同學的學號、姓名；
select Sid,Sname
from Student
where Sid in (select Sid from SC ,Course ,Teacher
where SC.Cid=Course.Cid and Teacher.Tid=Course.Tid and Teacher.Tname='葉平'
group by Sid having count(SC.Cid)=(select count(Cid) from Course,Teacher
where Teacher.Tid=Course.Tid and Tname='葉平'));
8、查詢課程編號“002”的成績比課程編號“001”課程低的所有同學的學號、姓名；
26 Select Sid,Sname from (select Student.Sid,Student.Sname,score ,(select score from SC SC_2
27 where SC_2.Sid=Student.Sid and SC_2.Cid='002') score2
28 from Student,SC where Student.Sid=SC.Sid and Cid='001') S_2 where score2 <score;
9、查詢所有課程成績小於60分的同學的學號、姓名；
29 select Sid,Sname
30 from Student
31 where Sid not in (select Student.Sid from Student,SC where S.Sid=SC.Sid and score>60);
10、查詢沒有學全所有課的同學的學號、姓名；
32 select Student.Sid,Student.Sname
33 from Student,SC
34 where Student.Sid=SC.Sid
35 group by Student.Sid,Student.Sname having count(Cid) <(select count(Cid) from Course);
11、查詢至少有一門課與學號為“1001”的同學所學相同的同學的學號和姓名；
36 select Sid,Sname from Student,SC
37 where Student.Sid=SC.Sid and Cid in select Cid from SC where Sid='1001';
12、查詢至少學過學號為“001”同學所有一門課的其他同學學號和姓名；
38 select distinct SC.Sid,Sname
39 from Student,SC
40 where Student.Sid=SC.Sid and Cid in (select Cid from SC where Sid='001');
13、把“SC”表中“葉平”老師教的課的成績都更改為此課程的平均成績；
41 update SC set score=(select avg(SC_2.score)
42 from SC SC_2
43 where SC_2.Cid=SC.Cid ) from Course,Teacher
44 where Course.Cid=SC.Cid and Course.Tid=Teacher.Tid and Teacher.Tname='葉平');
14、查詢和“1002”號的同學學習的課程完全相同的其他同學學號和姓名；
45 select Sid from SC where Cid in (select Cid from SC where Sid='1002')
46 group by Sid having count(*)=(select count(*) from SC where Sid='1002');
15、刪除學習“葉平”老師課的SC表記錄；
47 Delect SC
48 from course ,Teacher
49 where Course.Cid=SC.Cid and Course.Tid= Teacher.Tid 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“003”課程的同學學號、2、號課的平均成績；
50 Insert SC select Sid,'002',(Select avg(score)
51 from SC where Cid='002') from Student
52 where Sid not in (Select Sid from SC where Cid='002');
17、按平均成績從高到低顯示所有學生的“資料庫”、“企業管理”、“英語”三門的課程成績，按如下形式顯示： 學生ID,,資料庫,企業管理,英語,有效課程數,有效平均分
53 SELECT Sid as 學生ID
54 ,(SELECT score FROM SC WHERE SC.Sid=t.Sid AND Cid='004') AS 資料庫
55 ,(SELECT score FROM SC WHERE SC.Sid=t.Sid AND Cid='001') AS 企業管理
56 ,(SELECT score FROM SC WHERE SC.Sid=t.Sid AND Cid='006') AS 英語
57 ,COUNT(*) AS 有效課程數, AVG(t.score) AS 平均成績
58 FROM SC AS t
59 GROUP BY Sid
60 ORDER BY avg(t.score)
18、查詢各科成績最高和最低的分：以如下形式顯示：課程ID，最高分，最低分
61 SELECT L.Cid As 課程ID,L.score AS 最高分,R.score AS 最低分
62 FROM SC L ,SC AS R
63 WHERE L.Cid = R.Cid and
64 L.score = (SELECT MAX(IL.score)
65 FROM SC AS IL,Student AS IM
66 WHERE L.Cid = IL.Cid and IM.Sid=IL.Sid
67 GROUP BY IL.Cid)
68 AND
69 R.Score = (SELECT MIN(IR.score)
70 FROM SC AS IR
71 WHERE R.Cid = IR.Cid
72 GROUP BY IR.Cid
73 );
19、按各科平均成績從低到高和及格率的百分數從高到低順序
74 SELECT t.Cid AS 課程號,max(course.Cname)AS 課程名,isnull(AVG(score),0) AS 平均成績
75 ,100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分數
76 FROM SC T,Course
77 where t.Cid=course.Cid
78 GROUP BY t.Cid
79 ORDER BY 100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) DESC
20、查詢如下課程平均成績和及格率的百分數(用"1行"顯示): 企業管理（001），馬克思（002），OO&UML （003），資料庫（004）
80 SELECT SUM(CASE WHEN Cid ='001' THEN score ELSE 0 END)/SUM(CASE Cid WHEN '001' THEN 1 ELSE 0 END) AS 企業管理平均分
81 ,100 * SUM(CASE WHEN Cid = '001' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN Cid = '001' THEN 1 ELSE 0 END) AS 企業管理及格百分數
82 ,SUM(CASE WHEN Cid = '002' THEN score ELSE 0 END)/SUM(CASE Cid WHEN '002' THEN 1 ELSE 0 END) AS 馬克思平均分
83 ,100 * SUM(CASE WHEN Cid = '002' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN Cid = '002' THEN 1 ELSE 0 END) AS 馬克思及格百分數
84 ,SUM(CASE WHEN Cid = '003' THEN score ELSE 0 END)/SUM(CASE Cid WHEN '003' THEN 1 ELSE 0 END) AS UML平均分
85 ,100 * SUM(CASE WHEN Cid = '003' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN Cid = '003' THEN 1 ELSE 0 END) AS UML及格百分數
86 ,SUM(CASE WHEN Cid = '004' THEN score ELSE 0 END)/SUM(CASE Cid WHEN '004' THEN 1 ELSE 0 END) AS 資料庫平均分
87 ,100 * SUM(CASE WHEN Cid = '004' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN Cid = '004' THEN 1 ELSE 0 END) AS 資料庫及格百分數
88 FROM SC
21、查詢不同老師所教不同課程平均分從高到低顯示
89 SELECT max(Z.Tid) AS 教師ID,MAX(Z.Tname) AS 教師姓名,C.Cid AS 課程ID,MAX(C.Cname) AS 課程名稱,AVG(Score) AS 平均成績
90 FROM SC AS T,Course AS C ,Teacher AS Z
91 where T.Cid=C.Cid and C.Tid=Z.Tid
92 GROUP BY C.Cid
93 ORDER BY AVG(Score) DESC
22、查詢如下課程成績第 3 名到第 6 名的學生成績單：企業管理（001），馬克思（002），UML （003），資料庫（004） [學生ID],[學生姓名],企業管理,馬克思,UML,資料庫,平均成績
94 SELECT DISTINCT top 3
95 SC.Sid As 學生學號,
96 Student.Sname AS 學生姓名 ,
97 T1.score AS 企業管理,
98 T2.score AS 馬克思,
99 T3.score AS UML,
100 T4.score AS 資料庫,
101 ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) as 總分
102 FROM Student,SC LEFT JOIN SC AS T1
103 ON SC.Sid = T1.Sid AND T1.Cid = '001'
104 LEFT JOIN SC AS T2
105 ON SC.Sid = T2.Sid AND T2.Cid = '002'
106 LEFT JOIN SC AS T3
107 ON SC.Sid = T3.Sid AND T3.Cid = '003'
108 LEFT JOIN SC AS T4
109 ON SC.Sid = T4.Sid AND T4.Cid = '004'
110 WHERE student.Sid=SC.Sid and
111 ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0)
112 NOT IN
113 (SELECT
114 DISTINCT
115 TOP 15 WITH TIES
116 ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0)
117 FROM sc
118 LEFT JOIN sc AS T1
119 ON sc.Sid = T1.Sid AND T1.Cid = 'k1'
120 LEFT JOIN sc AS T2
121 ON sc.Sid = T2.Sid AND T2.Cid = 'k2'
122 LEFT JOIN sc AS T3
123 ON sc.Sid = T3.Sid AND T3.Cid = 'k3'
124 LEFT JOIN sc AS T4
125 ON sc.Sid = T4.Sid AND T4.Cid = 'k4'
126 ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) DESC);
23、統計列印各科成績,各分數段人數:課程ID,課程名稱,[100-85],[85-70],[70-60],[ <60]
127 SELECT SC.Cid as 課程ID, Cname as 課程名稱
128 ,SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85]
129 ,SUM(CASE WHEN score BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 - 70]
130 ,SUM(CASE WHEN score BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 - 60]
131 ,SUM(CASE WHEN score < 60 THEN 1 ELSE 0 END) AS [60 -]
132 FROM SC,Course
133 where SC.Cid=Course.Cid
134 GROUP BY SC.Cid,Cname;
24、查詢學生平均成績及其名次
135 SELECT 1+(SELECT COUNT( distinct 平均成績)
136 FROM (SELECT Sid,AVG(score) AS 平均成績
137 FROM SC
138 GROUP BY Sid
139 ) AS T1
140 WHERE 平均成績 > T2.平均成績) as 名次,
141 Sid as 學生學號,平均成績
142 FROM (SELECT Sid,AVG(score) 平均成績
143 FROM SC
144 GROUP BY Sid
145 ) AS T2
146 ORDER BY 平均成績 desc;
25、查詢各科成績前三名的記錄:(不考慮成績並列情況)
147 SELECT t1.Sid as 學生ID,t1.Cid as 課程ID,Score as 分數
148 FROM SC t1
149 WHERE score IN (SELECT TOP 3 score
150 FROM SC
151 WHERE t1.Cid= Cid
152 ORDER BY score DESC
153 )
154 ORDER BY t1.Cid;
26、查詢每門課程被選修的學生數
155 select cid,count(Sid) from sc group by Cid;
27、查詢出只選修了一門課程的全部學生的學號和姓名
156 select SC.Sid,Student.Sname,count(Cid) AS 選課數
157 from SC ,Student
158 where SC.Sid=Student.Sid group by SC.Sid ,Student.Sname having count(Cid)=1;
28、查詢男生、女生人數
159 Select count(Ssex) as 男生人數 from Student group by Ssex having Ssex='男';
160 Select count(Ssex) as 女生人數 from Student group by Ssex having Ssex='女'；
29、查詢姓“張”的學生名單
161 SELECT Sname FROM Student WHERE Sname like '張%';
30、查詢同名同性學生名單，並統計同名人數
162 select Sname,count(*) from Student group by Sname having count(*)>1;;
31、1981年出生的學生名單(注：Student表中Sage列的型別是datetime)
163 select Sname, CONVERT(char (11),DATEPART(year,Sage)) as age
164 from student
165 where CONVERT(char(11),DATEPART(year,Sage))='1981';
32、查詢每門課程的平均成績，結果按平均成績升序排列，平均成績相同時，按課程號降序排列
166 Select Cid,Avg(score) from SC group by Cid order by Avg(score),Cid DESC ;
33、查詢平均成績大於85的所有學生的學號、姓名和平均成績
167 select Sname,SC.Sid ,avg(score)
168 from Student,SC
169 where Student.Sid=SC.Sid group by SC.Sid,Sname having avg(score)>85;
34、查詢課程名稱為“資料庫”，且分數低於60的學生姓名和分數
170 Select Sname,isnull(score,0)
171 from Student,SC,Course
172 where SC.Sid=Student.Sid and SC.Cid=Course.Cid and Course.Cname='資料庫'and score <60;
35、查詢所有學生的選課情況；
173 SELECT SC.Sid,SC.Cid,Sname,Cname
174 FROM SC,Student,Course
175 where SC.Sid=Student.Sid and SC.Cid=Course.Cid ;
36、查詢任何一門課程成績在70分以上的姓名、課程名稱和分數；
176 SELECT distinct student.Sid,student.Sname,SC.Cid,SC.score
177 FROM student,Sc
178 WHERE SC.score>=70 AND SC.Sid=student.Sid;
37、查詢不及格的課程，並按課程號從大到小排列
179 select cid from sc where scor e <60 order by Cid ;
38、查詢課程編號為003且課程成績在80分以上的學生的學號和姓名；
180 select SC.Sid,Student.Sname from SC,Student
181 where SC.Sid=Student.Sid and Score>80 and Cid='003';
39、求選了課程的學生人數
182 select count(*) from sc;
40、查詢選修“葉平”老師所授課程的學生中，成績最高的學生姓名及其成績
183 select Student.Sname,score
184 from Student,SC,Course C,Teacher
185 where Student.Sid=SC.Sid and SC.Cid=C.Cid and C.Tid=Teacher.Tid and Teacher.Tname='葉平'
186 and SC.score=(select max(score)from SC where Cid=C.Cid );
41、查詢各個課程及相應的選修人數
187 select count(*) from sc group by Cid;
42、查詢不同課程成績相同的學生的學號、課程號、學生成績
188 select distinct A.Sid,B.score from SC A ,SC B where A.Score=B.Score and A.Cid <>B.Cid ;
43、查詢每門功成績最好的前兩名
189 SELECT t1.Sid as 學生ID,t1.Cid as 課程ID,Score as 分數
190 FROM SC t1
191 WHERE score IN (SELECT TOP 2 score
192 FROM SC
193 WHERE t1.Cid= Cid
194 ORDER BY score DESC
195 )
196 ORDER BY t1.Cid;
44、統計每門課程的學生選修人數（超過10人的課程才統計）。要求輸出課程號和選修人數，查詢結果按人數降序排列，查詢結果按人數降序排列，若人數相同，按課程號升序排列
197 select Cid as 課程號,count(*) as 人數
198 from sc
199 group by Cid
200 order by count(*) desc,cid
45、檢索至少選修兩門課程的學生學號
201 select Sid
202 from sc
203 group by sid
204 having count(*) > = 2
46、查詢全部學生都選修的課程的課程號和課程名
205 select Cid,Cname
206 from Course
207 where Cid in (select cid from sc group by cid)
47、查詢沒學過“葉平”老師講授的任一門課程的學生姓名
208 select Sname from Student where Sid not in (select Sid from Course,Teacher,SC
209 where Course.Tid=Teacher.Tid and SC.Cid=course.Cid and Tname='葉平');
48、查詢兩門以上不及格課程的同學的學號及其平均成績
210 select Sid,avg(isnull(score,0)) from SC
211 where Sid in (select Sid from SC where score <60
212 group by Sid having count(*)>2)group by Sid;
49、檢索“004”課程分數小於60，按分數降序排列的同學學號
213 select Sid from SC where Cid='004'and score <60 order by score desc;
50、刪除“002”同學的“001”課程的成績
214 delete from Sc where Sid='001'and Cid='001';