Informationen zur MySQL-Datenbank Eine Sammlung von Anweisungen zum Hinzufügen, Löschen, Ändern und Abfragen

CRUD操作：
create 创建（添加）
read 读取
update 修改
delete 删除

insert into Info values('p009','张三',1,'n001','2016-8-30 12:9:8') ; 
给特定的列添加数据
insert into Info (code,name) values('p010','李四');
自增长列的处理
insert into family values('','p001','数据','T001','数据',1);
insert into 表名 values(值)

删除所有数据
delete from family
删除特定的数据
delete from Info where code='p001'
delete from 表名 where 条件

修改所有数据
update Info set name='徐业鹏' 
修改特定数据
update Info set name='吕永乐' where code='p002' 
修改多列
update Info set name='吕永乐',sex=1 where code='p003' 
update 表名 set 要修改的内容 where 条件  tno =

(1)简单读取,查询所有列(*)  所有行（没有加条件）
select * from Info
(2)读取特定列
select code,name，class from Info
(3)条件查询
select * from Info where code='p003'
(4)多条件查询
select * from Info where code='p003' or nation='n002' #或的关系
select * from Info where sex=0 and nation='n002' #与的关系
(5)关键字查询（模糊查询）
查所有包含奥迪的汽车
select * from car where name like '%奥迪%'; #百分号%代表任意多个字符 
查以'皇冠'开头的所有汽车
select * from car where name like '皇冠%';
查询汽车名称中第二个字符是'马'的
select * from car where name like '_马%'; #下划线_代表任意一个字符
(6)排序查询
select * from car order by powers  #默认升序排列
select * from car order by powers  #升序asc 降序 desc
先按brand升序排，再按照price降序排
select * from car order by brand,price desc

select * from car where price9()>40 and price<60
select * from car where price between 40 and 60

select * from car where price=30 or price=40 or price=50 or price=60;
select * from car where price in(30,40,50,60)取出数据
select * from car where price not in(30,40,50,60)去掉数据

select count(*) from car
select count(code) from car #取所有的数据条数
select sum(price) from car #求价格总和
select avg(price) from car #求价格的平均值
select max(price) from car #求最大值
select min(price) from car #求最小值

select * from car limit 0,10  #分页查询，跳过几条数据(0)取几条(10)
规定一个每页显示的条数：m
当前页数：n]
select * from car limit (n-1)*m,m

select distinct brand from car

select brand,count(*) from car group by brand

select brand from car group by brand having（加条件） avg(price)>40

select brand from car group by brand having max(oil)>8

SELECT t1.Name,t2.Brand_Name FROM brand t2,car t1 -- 笛卡尔乘积
WHERE t2.Brand = t1.Brand

SELECT t1.Name,t2.Brand_Name,t3.prod_name  FROM car t1 LEFT JOIN brand t2 ON t1.Brand = t2.Brand
LEFT JOIN productor t3 ON t2.Prod = t3.Prod

SELECT `Name`,Price FROM car 
UNION
 SELECT Brand_Name,Brand_Memo FROM brand
-- 子查询（***）
SELECT * FROM car WHERE car.brand in (SELECT Brand FROM brand WHERE Prod = 'p001')