Mysql的知识梳理-百木园

数据准备:

--建表

create table  customer_jia(CID    int(4),
 Cname  varchar(20),
 Csex   varchar(2), 
 Cage   int(3),
 Cjob   varchar(20),
 CCNO   int(2)
);

create table  company_jia(CCNO    int(4),
 CCname  varchar(20),
 Cvalue    int(3),
 CADD    varchar(20)
);

新增数据

insert into customer_jia values(\'1002\',\'马化腾\',\'男\',\'49\',\'CEO\',\'02\');
insert into customer_jia values(\'1003\',\'黄铮\',\'男\',\'38\',\'CEO\',\'03\');
insert into customer_jia values(\'1004\',\'李彦宏\',\'男\',\'52\',\'CEO\',\'04\');
insert into customer_jia values(\'1005\',\'刘强东\',\'男\',\'55\',\'CEO\',\'05\');
insert into customer_jia values(\'1006\',\'张小龙\',\'男\',\'50\',\'CFO\',\'02\');
insert into customer_jia values(\'1007\',\'任正非\',\'男\',\'72\',\'董事长\',\'06\');
insert into customer_jia values(\'1008\',\'张三\',\'男\',\'80\',\'董事长\',\'07\');

新增数据

insert into company_jia values(\'2\',\'腾讯\',\'3885\',\'深圳\');
insert into company_jia values(\'3\',\'拼多多\',\'691\',\'上海\');
insert into company_jia values(\'4\',\'百度\',\'484\',\'北京\');
insert into company_jia values(\'5\',\'京东\',\'941\',\'北京\');
insert into company_jia values(\'6\',\'华为\',\'10000\',\'深圳\');
insert into company_jia values(\'7\',\'格力\',\'300\',\'深圳\');

-- 查询数据

select * from company_jia ;

select * from customer_jia a ,company_jia b where a.ccno=b.ccno;

插入数据:

insert into 表名 (值1,值2,值3);

修改数据:

update 表名 set 列名=值 where 列名=值;

删除:

delete from customer_jia where cname=刘强东; -------效率低，可恢复
truncate table customer_jia; --------一次性将数据或断，效率高，不可恢复,适合大量数据删除

drop table .customer_jia ; ----------删除表的同时把数据一起删除
行询

查询:

select 列名 from 表名 where 条件语句;

select 列名 from 表名 where 条件语句 order by 列名 desc;

模糊匹配: like

select 列名 from 表名 where 列名 like\"%R%\"; -----\"%\"代表0个或多个任意字符

select 列名 from 表名 where 列名 like\"R____\"; ------\"_\"代表一个任意字符

去重查询:distinct

select distinct 列名 from 表名 where 条件语句;

子查询:

当值用语法:select 列名 from 表名 where 列名=(select 列名 from 表名 where 条件语句);

当表用语法:select 列名 from (select 列名 from 表名 where 条件语句) 表别名 where 条件语句;

分组查询:

select 列名1,列名2 where 条件语句 group by 列名 ;

分组查询过滤:

select 列名1,列名2 where 条件语句 group by 列名 having 过滤条件;

表连接:

-- 内连接:

select * from customer_jia a inner join company_jia b on a.ccno=b.ccno;

-- 全连接: mysql 中没有full join 只是了解

select * from customer_jia a full outer join company_jia b on a.ccno=b.ccno;

select * from customer_jia a full join company_jia b on a.ccno=b.ccno;

-- 左连接:

select * from customer_jia a left join company_jia b on a.ccno=b.ccno;

-- 右连接:

select * from customer_jia a right join company_jia b on a.ccno=b.ccno;

-- 联合查询:union

(select * from customer_jia a left join company_jia b on a.ccno=b.ccno)
union
(select * from customer_jia a right join company_jia b on a.ccno=b.ccno);

-- 联合查询:union all

(select * from customer_jia a left join company_jia b on a.ccno=b.ccno)
union all
(select * from customer_jia a right join company_jia b on a.ccno=b.ccno);

来源：https://www.cnblogs.com/cn-zhouchao/p/16487644.html
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Mysql的知识梳理