MySQL links, rechts, innerer Join

mysql> select * from test10;
+------+-------+
| id | sname |
+------+-------+
| 1 | 云彩 | 
| 2 | 月亮 | 
| 3 | 星星 | 
+------+-------+

mysql> select * from test11;
+--------+-------+
| cat_id | cname |
+--------+-------+
| 95 | 猴子 | 
| 96 | 老虎 | 
+--------+-------+

mysql> select * from test10,test11;
+------+-------+--------+-------+
| id | sname | cat_id | cname |
+------+-------+--------+-------+
| 1 | 云彩 | 95 | 猴子 | 
| 1 | 云彩 | 96 | 老虎 | 
| 2 | 月亮 | 95 | 猴子 | 
| 2 | 月亮 | 96 | 老虎 | 
| 3 | 星星 | 95 | 猴子 | 
| 3 | 星星 | 96 | 老虎 | 
+------+-------+--------+-------+

mysql> select goods_id,minigoods.cat_id,goods_name,category.cat_id,cat_name from minigoods,category limit 3;
+----------+--------+--------------------+--------+----------+
| goods_id | cat_id | goods_name | cat_id | cat_name |
+----------+--------+--------------------+--------+----------+
| 1 | 4 | KD876 | 1 | 手机类型 | 
| 4 | 8 | htcN85原装充电器 | 1 | 手机类型 | 
| 3 | 8 | 诺基亚原装5800耳机 | 1 | 手机类型 | 
+----------+--------+--------------------+--------+----------+

mysql> insert into minigoods
-> select * from goods limit 3;

mysql> select goods_id,minigoods.cat_id,goods_name,category.cat_id,cat_name from minigoods,category where minigoods.cat_id=category.cat_id ;
+----------+--------+--------------------+--------+----------+
| goods_id | cat_id | goods_name | cat_id | cat_name |
+----------+--------+--------------------+--------+----------+
| 1 | 4 | KD876 | 4 | 3G手机 | 
| 4 | 8 | htcN85原装充电器 | 8 | 耳机 | 
| 3 | 8 | 诺基亚原装5800耳机 | 8 | 耳机 | 
+----------+--------+--------------------+--------+----------+

mysql> select goods_id,goods_name,cat_name 
-> from
-> (minigoods left join category on minigoods.cat_id=category.cat_id); 
+----------+--------------------+----------+
| goods_id | goods_name | cat_name |
+----------+--------------------+----------+
| 1 | KD876 | 3G手机 | 
| 4 | htcN85原装充电器 | 耳机 | 
| 3 | 诺基亚原装5800耳机 | 耳机 | 
+----------+--------------------+----------+

mysql> select goods_id,goods_name,cat_name from 
(minigoods left join category on minigoods.cat_id=category.cat_id )
where 1 order by goods_id desc limit 2; 
+----------+--------------------+----------+
| goods_id | goods_name | cat_name |
+----------+--------------------+----------+
| 4 | htcN85原装充电器 | 耳机 | 
| 3 | 诺基亚原装5800耳机 | 耳机 | 
+----------+--------------------+----------+

{{a left join b on [条件]} left join c on [条件]} 
mysql> select goods.goods_id,goods.goods_name,goods.cat_id,cat_name
-> from
-> minigoods left join category on minigoods.cat_id=category.cat_id
-> left join goods on minigoods.cat_id=4 limit 4;
+----------+--------------------+--------+----------+
| goods_id | goods_name | cat_id | cat_name |
+----------+--------------------+--------+----------+
| 1 | KD876 | 4 | 3G手机 | 
| 4 | htcN85原装充电器 | 8 | 3G手机 | 
| 3 | 诺基亚原装5800耳机 | 8 | 3G手机 | 
| 5 | 索爱原装M2卡读卡器 | 11 | 3G手机 | 
+----------+--------------------+--------+----------+

create table boy(
bname varchar(20),
other char(1)
)engine myisam charset utf8;
insert into boy
values
('屌丝','A'),
('李四','B'),
('王五','C'),
('高富帅','D'),
('郑七','E');

create table girl(
gname varchar(20),
other char(1)
)engine myisam charset utf8;
insert into girl
values
('空姐','B'),
('大S','C'),
('阿娇','D'),
('张柏芝','D'),
('林黛玉','E'),
('宝钗','F');

select boy.*,girl.* from
boy left join girl on
boy.other=girl.other;
+--------+-------+--------+-------+
| bname | other | gname | other |
+--------+-------+--------+-------+
| 屌丝 | A | NULL | NULL | 
| 李四 | B | 空姐 | B | 
| 王五 | C | 大S | C | 
| 高富帅 | D | 阿娇 | D | 
| 高富帅 | D | 张柏芝 | D | 
| 郑七 | E | 林黛玉 | E | 
+--------+-------+--------+-------+

mysql> select girl.*,boy.* from
-> girl left join boy on 
-> boy.other=girl.other;
+--------+-------+--------+-------+
| gname | other | bname | other |
+--------+-------+--------+-------+
| 空姐 | B | 李四 | B | 
| 大S | C | 王五 | C | 
| 阿娇 | D | 高富帅 | D | 
| 张柏芝 | D | 高富帅 | D | 
| 林黛玉 | E | 郑七 | E | 
| 宝钗 | F | NULL | NULL | 
+--------+-------+--------+-------+

mysql> select girl.* ,boy.* from
-> boy right join girl on
-> boy.other=girl.other;
+--------+-------+--------+-------+
| gname | other | bname | other |
+--------+-------+--------+-------+
| 空姐 | B | 李四 | B | 
| 大S | C | 王五 | C | 
| 阿娇 | D | 高富帅 | D | 
| 张柏芝 | D | 高富帅 | D | 
| 林黛玉 | E | 郑七 | E | 
| 宝钗 | F | NULL | NULL | 
+--------+-------+--------+-------+

select girl.*,boy.* from
boy inner join girl on 
boy.other=girl.other;
+--------+-------+--------+-------+
| gname | other | bname | other |
+--------+-------+--------+-------+
| 空姐 | B | 李四 | B | 
| 大S | C | 王五 | C | 
| 阿娇 | D | 高富帅 | D | 
| 张柏芝 | D | 高富帅 | D | 
| 林黛玉 | E | 郑七 | E | 
+--------+-------+--------+-------+

create table match_t(
match_id int primary key auto_increment,
host_team_id int,
guest_team_id int,
match_result varchar(20),
match_time date
)engine myisam charset utf8;
insert into match_t
values
(1,1,2,'2:0','2006-05-21'),
(2,2,3,'1:2','2006-06-21'),
(3,3,1,'2:5','2006-07-21'),
(4,1,1,'3:2','2006-08-21');
create table team_t(
team_id int primary key auto_increment,
team_name varchar(20)
)engine myisam charset utf8;
insert into team_t
values
(1,'恒大'),
(2,'国安'),
(3,'申花'),
(4,'大连');
mysql> select * from match_t;
+----------+--------------+---------------+--------------+------------+
| match_id | host_team_id | guest_team_id | match_result | match_time |
+----------+--------------+---------------+--------------+------------+
| 1 | 1 | 2 | 2:0 | 2006-05-21 | 
| 2 | 2 | 3 | 1:2 | 2006-06-21 | 
| 3 | 3 | 1 | 2:5 | 2006-07-21 | 
| 4 | 4 | 1 | 3:2 | 2006-08-21 | 
+----------+--------------+---------------+--------------+------------+
mysql> select * from team_t;
+---------+-----------+
| team_id | team_name |
+---------+-----------+
| 1 | 恒大 | 
| 2 | 国安 | 
| 3 | 申花 | 
| 4 | 大连 | 
+---------+-----------+