--1.创建classes表
CREATE TABLE classes(
id INT,
name VARCHAR(20)
)
--2.创建students表
CREATE TABLE Students(
id INT,
name VARCHAR(20),
birthday VARCHAR(21),
gender VARCHAR(20),
score int,
class_id int
)
--3.班级表中添加三条数据
insert INTO classes (id ,name)VALUES(1,'一年级') ,(2,'二年级'),(3,'三年级')
--4.在学生表添加六条数据
insert INTO Students(id,name,birthday,gender,score,class_id)VALUES
(1,"张三","2010-11-10","男",100,1),
(2,"李四","2012-11-10","女",75,1),
(3,"王五","2014-11-10","男",80,2),
(4,"小明","2013-11-10","女",60,2),
(5,"小李","2015-11-10","女",30,2),
(6,"小刘","2008-11-10","男",90,3)
--5.查询平均分
select AVG(score)from students
--6.修改张三的名字为张五
UPDATE students SET name ='张五'where name='张三'
--7.删除班级名字为”三年级”的所有学生
DELETE from students where class_id='3'
--8.查询一年级分数最高的人
select MAX(score)FROM students WHERE class_id=1
--9.查询所有学生的年级信息（用子查询实现）
SELECT classes.name,students.name FROM classes ,students where students.class_id=classes.id
--10.查询以‘小’开头的名字为一个字学生
SELECT students.name FROM students where students.name LIKE'小%'
--11.查询出生日期在2008-11-10到2012-11-10的学生
select students.name FROM students WHERE birthday between '2008-11-10' AND '2012-11-10'
--1.创建一个分类表(cate)，包含字段id,name
create table cate(
id int ,
name VARCHAR(20)
)
--2.创建一个商品表(goods),包含字段id,name,number,create_time,price,cate_id
CREATE table goods(
id int,
name VARCHAR(20),
number INT,
create_time VARCHAR(20),
price DOUBLE,
cate_id INT
)
--3.在分类表中添加三条记录 id:1 name:服装，id:2 name:玩具，id:3 name:家电
insert into cate(id,name)VALUES(1,'服装'),(2,'玩具'),(3,'家电')
--4.在商品表里添加六条记录，
INSERT INTO goods(id,name,number,create_time,price,cate_id)VALUES
(1,'羽绒服',10,'2010-11-10',1.00,1),
(2,'轻便服',30,'2012-11-10',2.00,1),
(3,'汽车',40,'2014-11-10',2.00,2),
(4,'公主',50,'2013-11-10',6.00,2),
(5,'橡皮泥',23,'2015-11-10',3.50,2),
(6,'轻便服',30,'2012-11-10',2.00,1),
(7,'电饭煲',3,'2008-11-10',3.00,3)
--5.使用pymysql模块来查询所有的分类及商品
select cate.name,goods.name FROM cate,goods
--6.把名字为‘羽绒服’修改成‘棉衣
UPDATE goods SET name ='棉衣'where name='羽绒服'
--7. 删除名字为‘电饭煲’的记录
DELETE FROM goods where name='电饭煲'
--8.查询‘服装’分类下面库存最多的商品信息
SELECT MAX(goods.number)FROM goods
--9.查询分类下有商品分类信息
select cate.name , goods.name FROM cate ,goods where goods.cate_id = cate.id
--10.查询以‘服’结束的商品信息
SELECT goods.name FROM goods where goods.name LIKE'%服'
--11.查询创建日期在2008-11-10到2012-11-10的之间的商品
select goods.name FROM goods WHERE create_time between '2008-11-10' AND '2012-11-10'
三：
--1.创建一个数据库 cart
create DATABASE cart
--2.创建用户表
create table userd(
id int ,
name VARCHAR(20),
height DOUBLE
)
--3.创建购物车表
create table user_cart(
id int ,
name VARCHAR(20),
number int,
price INT,
del VARCHAR(10),
user_id int
)
--5.添加数据
INSERT INTO userd(id ,name,height)VALUES(1,'张三',1.80),(2,'李四',1.75),(3,'小明',1.34)
--6.在购物车表中加入以下记录（1代表未删除，0代表删除）
INSERT INTO user_cart(id,name,number,price,del,user_id)VALUES
(1,'商品一',10,100,1,1),
(2,'商品二',3,89,0,1),
(3,'商品三',2,30,1,1),
(4,'商品四',10,50,1,2),
(5,'商品五',3,10,1,2),
(6,'商品六',1,76,1,2)
--7.更新李四的购物车中 商品五的名字为商品5
UPDATE user_cart SET name = '商品5' where user_cart.id = 5
--8.查询身高大于1米并且购物车没删除的用户和购物车信息(叉)
select user_cart.name,userd.name FROM userd,user_cart where userd.height>1
--9.查询购物车中删除和没删除的总价和为多少
SELECT SUM(user_cart.price) FROM user_cart where user_cart.del=1
SELECT SUM(user_cart.price) FROM user_cart where user_cart.del=0
--10.查询每个用户没删除的购物车的数量大于1的记录，并按降序排列，取三条记录(?)
SELECT user_cart.number FROM user_cart ORDER BY DESC WHERE user_cart.del =1
-- 11.按是否删除分组，查询平均总价格大于10的用户和购物车信息
SELECT * FROM user_cart c
GROUP BY deleteu
HAVING sum(c.price)/count(*)>10
-- 12.查询有购物车的用户和购物车信息
select * from users u right JOIN user_cart c ON c.uid=u.id WHERE c.deleteu=1
-- 13.删除张三购物车中已删除的购物车信息
delete FROM user_cart c, users u WHERE c.deleteu=0 AND u.uname="张三"
