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本篇内容介绍了“MySQL中的join、left join和right join的用法”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
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暂时先用两个表来演示：
创建bro_cats表：
create table bro_cats(
id int(11) not null auto_increment,
name varchar(128) not null default '',
desn varchar(128) not null default '',
primary key()
);
创建bro_articles表：
create table bro_articles(
id int not null auto_increment,
cid int not null,
name varchar(128) not null,
content test not null,
primary key(id)
);
接下来我们向里边插入数据
INSERT INTO bro_cats(name, desn) values(‘php’,’php demo’);
INSERT INTO bro_cats(name, desn) values(‘jsp’,’jsp demo’);
INSERT INTO bro_cats(name, desn) values(‘’,’asp demo’);
INSERT INTO bro_articles(cid, name, content) //php 类中 cid=1
values(1,’this article of php1’, ‘php content1’);
INSERT INTO bro_articles(cid, name, content) //php 类中 cid=1
values(1,’this article of php2’, ‘php content2’);
INSERT INTO bro_articles(cid, name, content) // 类中 cid=2
values(2,’this article of jsp’, ‘jsp content’);
INSERT INTO bro_articles(cid, name, content) //asp 类中 cid=3
values(3,’this article of asp1’, ‘asp content1’);
INSERT INTO bro_articles(cid, name, content) //asp 类中 cid=3
values(3,’this article of asp2’, ‘asp content2’);
下一步我们就用join语句测试一下
左联接：left join
select bro_cats.name as catsname,bro_cats.desn as description,bro_articles.name as articlesname,bro_articles.content as articlecontent from bro_cats left join bro_articles on bro_cats.id = bro_articles.cid;
右联接：right join
select bro_cats.name as catsname,bro_cats.desn as description,bro_articles.name as articlesname,bro_articles.content as articlecontent from bro_cats right join bro_articles on bro_cats.id = bro_articles.cid;
联接：join
select bro_cats.name as catsname,bro_cats.desn as description,bro_articles.name as articlesname,bro_articles.content as articlecontent from bro_cats join bro_articles on bro_cats.id = bro_articles.cid;
具体的这三个是什么效果，我还是建议大家试一下比较一下自己得出结论。
“mysql中的join、left join和right join的用法”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注创新互联网站，小编将为大家输出更多高质量的实用文章！
