剑指架构师系列-MySQL常用SQL语句

select a.Sno from
(select Sno,score from SC where Cno=1 ) as a,
(select Sno,score from SC where Cno=2 ) as b
 where a.score>b.score and a.Sno=b.Sno;　

SELECT Sno,AVG(score) FROM SC
GROUP BY Sno HAVING AVG(score) >60;

SELECT Student.Sno,Student.Sname,COUNT(SC.Cno),SUM(SC.score)
FROM Student 
LEFT OUTER JOIN SC ON Student.Sno=SC.Sno
GROUP BY Student.Sno,Sname;

SELECT COUNT(DISTINCT(Tname))  FROM Teacher
WHERE Tname LIKE ‘李%‘;

SELECT Student.Sno,Student.Sname
FROM Student 
WHERE Sno NOT IN 
(
  SELECT DISTINCT(SC.Sno) FROM SC,Course,Teacher 
  WHERE  SC.Cno=Course.Cno AND Teacher.Tno=Course.Tno AND Teacher.Tname=‘李小风‘
);

SELECT Student.Sno,Student.Sname 
FROM   Student,SC
WHERE  Student.Sno=SC.Sno 
AND    SC.Cno=1
AND    EXISTS( SELECT * FROM SC AS SC_2 WHERE SC_2.Sno=SC.Sno AND SC_2.Cno=2 )
-- 查询同时学过1、2、3的课程
-- AND EXISTS( SELECT * FROM SC AS SC_3 WHERE SC_3.Sno=SC.Sno AND SC_3.Cno=3 )

SELECT Sno,Sname
FROM   Student
WHERE Sno IN (
    SELECT Sno 
    FROM   SC,Course ,Teacher 
    WHERE  SC.Cno=Course.Cno AND Teacher.Tno=Course.Tno AND Teacher.Tname=‘李小风‘
    GROUP BY Sno  HAVING COUNT(SC.Cno)=(
                            SELECT COUNT(Cno) FROM  Course,Teacher
                            WHERE Teacher.Tno=Course.Tno AND Tname=‘李小风‘
                         )
);

SELECT Sno,Sname
FROM   Student
WHERE  Sno NOT IN (
                    SELECT Student.Sno FROM Student,SC WHERE Student.Sno=SC.Sno AND score>60
                  );

SELECT Student.Sno,Student.Sname
FROM   Student,SC
WHERE  Student.Sno=SC.Sno 
GROUP BY Student.Sno,Student.Sname 
HAVING COUNT(SC.Cno) <(SELECT COUNT(Course.Cno) FROM Course );

SELECT s.Sno,s.Sname 
FROM Student s 
GROUP BY s.Sno,s.Sname HAVING s.Sno IN ( SELECT Course.Cno FROM Course,SC WHERE SC.Sno=1 )

SELECT s.Sno,s.Sname 
FROM Student s,SC sc 
WHERE s.Sno=sc.Sno AND sc.Cno IN ( SELECT Course.Cno FROM Course,SC WHERE SC.Sno=1 ) 
GROUP BY s.Sno

UPDATE SC,Course,Teacher 
SET SC.score=( SELECT AVG(SC_2.score) FROM (SELECT * FROM SC) AS SC_2 WHERE SC_2.Cno=SC.Cno )
WHERE Course.Cno=SC.Cno AND Course.Tno=Teacher.Tno AND Teacher.Tname=‘李力‘;

SELECT Sno 
FROM   SC 
WHERE  Cno IN(SELECT Cno FROM SC WHERE Sno=2)
GROUP BY Sno HAVING COUNT(*)=(SELECT COUNT(*) FROM SC WHERE Sno=2);

 DELETE SC
 FROM   Course,Teacher,SC
 WHERE  Course.Cno=SC.Cno AND Course.Tno=Teacher.Tno AND Tname=‘李力‘;

INSERT SC 
  SELECT Sno,2,
  (
      SELECT AVG(score) FROM SC WHERE Cno=2
  ) 
  FROM Student WHERE Sno NOT IN (SELECT Sno FROM SC WHERE Cno=3);

SELECT Sno AS 学生ID
        ,(SELECT score FROM SC WHERE SC.Sno=t.Sno AND Cno=4) AS 高数
        ,(SELECT score FROM SC WHERE SC.Sno=t.Sno AND Cno=1) AS C语言
        ,(SELECT score FROM SC WHERE SC.Sno=t.Sno AND Cno=6) AS Java程序高级设计
        ,COUNT(*) AS 有效课程数, AVG(t.score) AS 平均成绩
    FROM SC AS t
    GROUP BY Sno
    ORDER BY AVG(t.score)

 SELECT SC.Cno,MAX(score),MIN(score)
 FROM SC 
 GROUP BY Cno

SELECT 
  t.Cno AS 课程号,
  MAX(c.Cname) AS 课程名,
  IFNULL(AVG(t.score),0) AS 平均成绩,
  100 * SUM(CASE WHEN  IFNULL(t.score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数
FROM SC t,Course c
WHERE t.Cno=c.Cno
GROUP BY t.Cno
ORDER BY 及格百分数 DESC   
  

SELECT 
	MAX(Z.Tno) AS 教师ID,
	MAX(Z.Tname) AS 教师姓名,
	C.Cno AS 课程ID,
	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.Cno=C.Cno AND C.Tno=Z.Tno 
GROUP BY C.Cno 
ORDER BY 平均成绩 DESC

SELECT  
        SC.Sno AS 学生学号, 
        Student.Sname AS 学生姓名, 
        T1.score AS 高数, 
        T2.score AS C语言, 
        T3.score AS Java高级程序设计, 
        T4.score AS 数据结构与算法, 
        IFNULL(T1.score,0) +IFNULL(T2.score,0) +IFNULL(T3.score,0) +IFNULL(T4.score,0) AS 总分 
        FROM Student,SC  
            LEFT JOIN SC AS T1  ON SC.Sno = T1.Sno AND T1.Cno =1
            LEFT JOIN SC AS T2  ON SC.Sno = T2.Sno AND T2.Cno =2
            LEFT JOIN SC AS T3  ON SC.Sno = T3.Sno AND T3.Cno =3
            LEFT JOIN SC AS T4  ON SC.Sno = T4.Sno AND T4.Cno =4
        WHERE Student.Sno=SC.Sno 
        GROUP BY SC.Sno
        ORDER BY 总分 DESC
        LIMIT 3,3

SELECT  SC.Cno 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.Cno=Course.Cno
    GROUP BY SC.Cno,Cname; 

SELECT 1+( SELECT COUNT(DISTINCT 平均成绩) 
	   FROM ( SELECT Sno,AVG(score) AS 平均成绩 FROM SC GROUP BY Sno ) AS T1 
	   WHERE 平均成绩 > T2.平均成绩

      ) AS 名次, Sno AS 学生学号,平均成绩 
FROM (SELECT Sno,AVG(score) AS 平均成绩 FROM SC  GROUP BY Sno) AS T2 
ORDER BY 平均成绩 DESC; 

SELECT t1.Sno AS 学生ID,t1.Cno AS 课程ID,Score AS 分数 
FROM SC t1 
WHERE score IN (
	  SELECT score FROM SC 
	  WHERE t1.Cno=Cno 
	  ORDER BY score DESC
	  LIMIT 0,3 
) 
ORDER BY t1.Cno; 

This version of MySQL doesn‘t yet support ‘LIMIT & IN/ALL/ANY/SOME subquery‘

 SELECT SC.Sno,Student.Sname,COUNT(Cno) AS 选课数 
 FROM SC ,Student 
 WHERE SC.Sno=Student.Sno 
 GROUP BY SC.Sno ,Student.Sname HAVING COUNT(Cno)=1; 

SELECT  Sname,CAST(DATE_FORMAT(Sbirthday,‘%Y-%m-%d‘) AS CHAR(13)) AS birthday 
FROM    Student
WHERE   CAST(DATE_FORMAT(Sbirthday,‘%Y-%m-%d‘) AS CHAR(13))=‘2015-09-16‘ ; 

SELECT Cno,AVG(score) FROM SC GROUP BY Cno ORDER BY AVG(score),Cno DESC ;

SELECT Student.Sname,score 
FROM Student,SC,Course C,Teacher 
WHERE Student.Sno=SC.Sno AND SC.Cno=C.Cno AND C.Tno=Teacher.Tno AND Teacher.Tname=‘李小风‘ AND 
SC.score=(SELECT MAX(score) FROM SC WHERE Cno=C.Cno );
-- 如下的语句是错误的
SELECT Student.Sname,score 
FROM Student,SC,Course C,Teacher 
WHERE Student.Sno=SC.Sno AND SC.Cno=C.Cno AND C.Tno=Teacher.Tno AND Teacher.Tname=‘李小风‘ 
ORDER BY SC.score DESC 
LIMIT 1

select std.Sno,std.Sname from student std,SC sc where std.Sno=sc.Sno group by std.Sno having count(distinct(sc.Cno))>2