成绩表
多表查询sql语句
1、表架构
student(sid,sname,sage,ssex) 学生表
course(cid,cname,tid) 课程表
sC(sid,cid,score) 成绩表
teacher(tid,tname) 教师表
2、建表sql语句
CREATE TABLE student
(
sid INT PRIMARY KEY NOT NULL,
sname VARCHAR(30),
sage INT,
ssex VARCHAR(8)
)
CREATE TABLE course
(
cid INT PRIMARY KEY NOT NULL,
cname VARCHAR(30),
tid INT
)
CREATE TABLE sc
(
sid INT NOT NULL,
cid INT NOT NULL,
score INT
)
CREATE TABLE teacher
(
tid INT PRIMARY KEY NOT NULL,
tname VARCHAR(30)
)
3、问题：
（1）查询“30001”课程的所有学生的学号与分数；
SELECT sid,score FROM sc WHERE cid="30001"
（2）查询“001”课程比“002”课程成绩高的所有学生的学号与分数；
SELECT a.sid,a.score FROM (SELECT sid,score FROM sc WHERE cid="30001") a,
(SELECT sid,score FROM sc WHERE cid="30002") b
WHERE a.score>b.score AND a.sid=b.sid
（3）查询平均成绩大于60分的同学的学号和平均成绩；
SELECT sid,AVG(score)
FROM sc
GROUP BY sid HAVING AVG(score)>60
（4）查询所有同学的学号、姓名、选课数、总成绩
SELECT s.sid AS "学号", s.sname AS "姓名", COUNT(sc.cid) AS "课程数目", SUM(sc.score) AS "总分数"
FROM student s, sc sc
WHERE s.sid=sc.sid
GROUP BY s.sid
（5）查询姓“李”的老师的个数；
select count(distinct(Tname))
from teacher
where tname like '李%';
（6）查询学过“张三”老师课的同学的学号、姓名
SELECT s.sid AS "学号", s.sname AS "姓名"
FROM student s, sc sc, course c, teacher t
WHERE s.sid=sc.sid AND c.cid=sc.cid AND t.tid=c.tid AND t.tname="张三"
（7）查询没有学过“张三”老师课的同学的学号、姓名
SELECT s.sid, s.sname
FROM student s
WHERE s.sid NOT IN (
SELECT s.sid
FROM student s, sc sc, course c, teacher t
WHERE s.sid=sc.sid AND c.cid=sc.cid AND t.tid=c.tid AND t.tname="张三"
)
（8）查询学过“30001”并且也学过编号“30002”课程的同学的学号、姓名
SELECT s.sid, s.sname
FROM student s, sc sc
WHERE s.sid=sc.sid AND sc.cid="30001" AND exists(
SELECT * FROM sc AS sc2 WHERE sc2.sid=sc.sid AND sc2.cid="30002"
)
（9）查询学过“叶平”老师所教的所有课的同学的学号、姓名；
SELECT sid, sname
FROM student
WHERE sid IN (
SELECT sc.sid
FROM sc sc, course c, teacher t
WHERE sc.cid=c.cid AND c.tid=t.tid AND t.tname="张二"
)
（10）查询所有课程成绩小于60分的同学的学号、姓名
SELECT sid, sname FROM student
WHERE sid NOT IN (
SELECT DISTINCT(sc.sid) FROM student s, sc sc
WHERE sc.sid=s.sid AND sc.score>60)
（11）查询没有学全所有课的同学的学号、姓名；
SELECT sid, sname FROM student
WHERE sid NOT IN(
SELECT s.sid FROM student s, sc sc
WHERE sc.sid=s.sid
GROUP BY s.sid
HAVING COUNT(sc.cid)=(
SELECT COUNT(cid) FROM course))
（12）查询各科成绩最高和最低的分：以如下形式显示：课程ID，最高分，最低分
SELECT cid AS "课程ID", MAX(score) AS "最高分", MIN(score) AS "最低分"
FROM sc
GROUP BY cid
（13）按各科平均成绩从低到高和及格率的百分数从高到低顺序
(方式一)
SELECT sc.cid AS "课程ID",c.cname AS "课程名", AVG(sc.score) AS "平均成绩",
SUM(CASE WHEN sc.score > 60 THEN 1 ELSE 0 END)/COUNT(1)*100 AS "及格百分数"
FROM sc sc, course c
WHERE sc.cid=c.cid
GROUP BY sc.cid
order BY AVG(sc.score) ASC,
SUM(CASE WHEN sc.score > 60 THEN 1 ELSE 0 END)/COUNT(1)*100 DESC
(方式二)
SELECT sc.cid AS "课程ID",c.cname AS "课程名", IFNULL(AVG(sc.score),0) AS "平均成绩",
100*SUM(CASE WHEN IFNULL(sc.score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS "及格百分数"
FROM sc sc, course c
WHERE sc.cid = c.cid
GROUP BY sc.cid
ORDER BY AVG(sc.score) ASC,
100*SUM(CASE WHEN IFNULL(sc.score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) DESC
（14）查询所有学生的所有科目的成绩单（学号、姓名、语文、数学、英语、物理、平均分、总分（按照总分由高到低排序））
SELECT s.sid AS "学号", s.sname AS "姓名",
SUM(CASE c.cname WHEN "语文" THEN sc.score ELSE 0 END) AS "语文",
SUM(CASE c.cname WHEN "数学" THEN sc.score ELSE 0 END) AS "数学",
SUM(CASE c.cname WHEN "英语" THEN sc.score ELSE 0 END) AS "英语",
SUM(CASE c.cname WHEN "物理" THEN sc.score ELSE 0 END) AS "物理",
IFNULL(AVG(sc.score),0) AS "平均分",
IFNULL(SUM(sc.score),0) AS "总分"
FROM student s
LEFT OUTER JOIN sc sc ON s.sid=sc.sid
LEFT OUTER JOIN course c ON sc.cid=c.cid
GROUP BY s.sid, s.sname
ORDER BY IFNULL(SUM(sc.score),0) DESC
（15）查询总分排名在200-300（包含200和第300）之间的学生所有成绩单信息
SELECT s.sid AS "学号", s.sname AS "姓名",
SUM(CASE c.cname WHEN "语文" THEN sc.score ELSE 0 END) AS "语文",
SUM(CASE c.cname WHEN "数学" THEN sc.score ELSE 0 END) AS "数学",
SUM(CASE c.cname WHEN "英语" THEN sc.score ELSE 0 END) AS "英语",
SUM(CASE c.cname WHEN "物理" THEN sc.score ELSE 0 END) AS "物理",
IFNULL(AVG(sc.score),0) AS "平均分",
IFNULL(SUM(sc.score),0) AS "总分"
FROM student s
LEFT OUTER JOIN sc sc ON s.sid=sc.sid
LEFT OUTER JOIN course c ON sc.cid=c.cid
GROUP BY s.sid, s.sname
HAVING IFNULL(SUM(sc.score),0) BETWEEN 200 AND 300
ORDER BY IFNULL(SUM(sc.score),0) DESC
（16）查询总分排名在前四名的学生所有成绩单信息
SELECT s.sid AS "学号", s.sname AS "姓名",
SUM(CASE c.cname WHEN "语文" THEN sc.score ELSE 0 END) AS "语文",
SUM(CASE c.cname WHEN "数学" THEN sc.score ELSE 0 END) AS "数学",
SUM(CASE c.cname WHEN "英语" THEN sc.score ELSE 0 END) AS "英语",
SUM(CASE c.cname WHEN "物理" THEN sc.score ELSE 0 END) AS "物理",
IFNULL(AVG(sc.score),0) AS "平均分",
IFNULL(SUM(sc.score),0) AS "总分"
FROM student s
LEFT OUTER JOIN sc sc ON s.sid=sc.sid
LEFT OUTER JOIN course c ON sc.cid=c.cid
GROUP BY s.sid, s.sname
ORDER BY IFNULL(SUM(sc.score),0) DESC
limit 0,4
（17）查询总分排名在前二名到四名的学生所有成绩单信息（limit 1,3表示从第二条数据开始，连续三条数据）
SELECT s.sid AS "学号", s.sname AS "姓名",
SUM(CASE c.cname WHEN "语文" THEN sc.score ELSE 0 END) AS "语文",
SUM(CASE c.cname WHEN "数学" THEN sc.score ELSE 0 END) AS "数学",
SUM(CASE c.cname WHEN "英语" THEN sc.score ELSE 0 END) AS "英语",
SUM(CASE c.cname WHEN "物理" THEN sc.score ELSE 0 END) AS "物理",
IFNULL(AVG(sc.score),0) AS "平均分",
IFNULL(SUM(sc.score),0) AS "总分"
FROM student s
LEFT OUTER JOIN sc sc ON s.sid=sc.sid
LEFT OUTER JOIN course c ON sc.cid=c.cid
GROUP BY s.sid, s.sname
ORDER BY IFNULL(SUM(sc.score),0) DESC
LIMIT 1,3
（18）查询学生平均成绩及其名次
(非本人)
SELECT 1+(SELECT COUNT( distinct 平均成绩)
FROM (
SELECT sid,AVG(score) AS 平均成绩
FROM sc
GROUP BY sid ) AS T1
WHERE 平均成绩 > T2.平均成绩) as 名次, S# as 学生学号,平均成绩
FROM (SELECT sid,AVG(score) 平均成绩
FROM sc GROUP BY sid ) AS T2
ORDER BY 平均成绩 desc
相关阅读
我们平时在编辑excel表格的时候，难免要输入身份证号，很多朋友应该都会有一个疑问，输入身份证号之后会显示乱码出来，然后就去重新输入
现在刚毕业的大学生都比较倾向于做微商，毕竟在家就能轻轻松松赚钱。但是由于学生对于做这些都是没有什么经验，经常会做亏本生意。学
create table ,create table as 与create like三种建
Hive的hql是基于sql而来，而sql中关于表的创建有几种方式。同样，hive也支持这些表的创建方式。 官网文档关于建表的地址：hive常见建表
《给教师的一百条建议》读后感3500字：初读苏霍姆林斯基的《给教师的一百条建议》这本书，是因为招聘考试中经常会涉及到苏联著名教育
这篇文章在我所写文章里面，耗时最长，不是因为它很复杂，而是要写清楚它的可操作性确实是一件不易的事情，这里要感谢为我指出文章问题的