3.13作业

CREATE TABLE GRADE(
ID INT PRIMARY KEY AUTO_INCREMENT COMMENT'学号',
NAME VARCHAR(20) COMMENT'姓名',
AGE INT COMMENT'年龄',
CLASS INT COMMENT'班级',
CHINESE INT COMMENT'语文分数',
ENGLISH INT COMMENT'英语分数',
MATH INT COMMENT'数学分数')
ENGINE=INNODB DEFAULT CHARSET=UTF8 COMMENT'学生表';

#插入表数据
/*insert into GRADE values
(1,'zhangsan',18,1832,80,90,77),
(2,'lisi',18,1832,90,90,90),
(3,'wangwu',19,1833,99,98,100),
(4,'zhaoliu',17,1833,85,78,85),
(5,'xiaoqi',17,1832,60,80,88),
(6,'xiaoba',18,1833,70,82,90);*/
/*insert into GRADE values
(7,'xiaoyi',19,1833,89,87,89),
(8,'xiaoer',17,1832,79,88,90),
(9,'xioasan',18,1833,88,98,100),
(10,'xioasi',18,1832,85,86,85),
(11,'xiaowu',17,1832,56,97,88),
(12,'xioaliu',18,1833,70,82,61);*/
INSERT INTO GRADE VALUES(13,'xiaoqi',18,1832,88,98,77);
INSERT INTO GRADE(NAME,AGE) VALUES('xiaoba',18);

1，查询1832班的成绩信息
SELECT * from GRADE WHERE CLASS=1832;
2，查询1833班，语文成绩大于80小于90的所有成绩信息
select ID,NAME,CLASS,CHINESE from GRADE where class=1833 and CHINESE BETWEEN 80 AND 90;
3，查询学生表中5到10行的数据
SELECT * FROM GRADE limit 4,6;
4，显示1832班英语成绩为98，数学成绩为77的姓名与学号,
select ID,name from GRADE WHERE ENGLISH=98 AND MATH=77;
5，查询出1832班成绩并且按语文成绩排序（降序）
SELECT * FROM GRADE WHERE CLASS=1832 ORDER BY CHINESE DESC;
6，查询1833班与1832班，语文成绩与数学成绩都小于80的姓名。
SELECT * FROM GRADE WHERE CHINESE<80 AND MATH<80;
7，查询出没有参加语文考试的学生姓名和班级名称。
SELECT NAME,CLASS FROM GRADE WHERE CHINESE IS NULL;
8，求出班上语文成绩不及格的学生姓名
SELECT * FROM GRADE WHERE CHINESE<60;
9，求出每个班的数学平均成绩
SELECT CLASS,AVG(MATH) FROM GRADE GROUP BY CLASS;
10、求出每个班级语文成绩总分 --涉及到每个的时候都需要分组
SELECT CLASS,SUM(CHINESE) FROM GRADE GROUP BY CLASS;
11、将语文成绩不及格的学生语文成绩改为60分
UPDATE GRADE SET CHINESE=60 WHERE CHINESE<60;
12、三科分数都大于70分的人名和年纪
SELECT NAME,AGE FROM GRADE WHERE CHINESE>70 AND ENGLISH>70 AND MATH>70;
13、求出英语分数高于70且其它任何一科目大于60分的人和班级
SELECT NAME,CLASS FROM GRADE WHERE ENGLISH>70 AND (CHINESE>60 OR MATH>60);
14、统计每个班的人数
SELECT CLASS,COUNT(*) FROM GRADE GROUP BY CLASS;
15、求每个班数学成绩大于80的人数
SELECT COUNT(*),CLASS FROM GRADE WHERE MATH>80 GROUP BY CLASS;
16、求出每个班英语成绩最高的分数和班级名称 --每个班英语成绩最高
SELECT MAX(ENGLISH),CLASS,NAME FROM GRADE GROUP BY CLASS;
17、给GRADE表增加3个字段（数据类型及长度自定义，建议要合理，
ALTER TABLE GRADE ADD TEL INT,ADD HEIGHT FLOAT(3,2),ADD WEIGHT FLOAT(3,2);