目錄：

• 資料
• 建表
• 操作

正文：

1、資料

a:
+-------+---------+--+
| a.id  | a.name  |
+-------+---------+--+
| 1     | a       |
| 2     | b       |
| 3     | c       |
| 4     | d       |
| 7     | y       |
| 8     | u       |
+-------+---------+--+

b:
+-------+---------+--+
| b.id  | b.name  |
+-------+---------+--+
| 2     | bb      |
| 3     | cc      |
| 7     | yy      |
| 9     | pp      |
+-------+---------+--+

2、建表

create table a(id int,name string)
row format delimited
fields terminated by ',';

create table b(id int,name string)
row format delimited
fields terminated by ',';

load data local inpath '/home/hadoop/a.txt' into table a;
load data local inpath '/home/hadoop/b.txt' into table b;

3、操作

inner join 操作

select * from a inner join b on a.id=b.id;

+-------+---------+-------+---------+--+
| a.id  | a.name  | b.id  | b.name  |
+-------+---------+-------+---------+--+
| 2     | b       | 2     | bb      |
| 3     | c       | 3     | cc      |
| 7     | y       | 7     | yy      |
+-------+---------+-------+---------+--+

left join 操作

select * from a left join b on a.id=b.id;

+-------+---------+-------+---------+--+
| a.id  | a.name  | b.id  | b.name  |
+-------+---------+-------+---------+--+
| 1     | a       | NULL  | NULL    |
| 2     | b       | 2     | bb      |
| 3     | c       | 3     | cc      |
| 4     | d       | NULL  | NULL    |
| 7     | y       | 7     | yy      |
| 8     | u       | NULL  | NULL    |
+-------+---------+-------+---------+--+

right join 操作

select * from a right join b on a.id=b.id;

+-------+---------+-------+---------+--+
| a.id  | a.name  | b.id  | b.name  |
+-------+---------+-------+---------+--+
| 2     | b       | 2     | bb      |
| 3     | c       | 3     | cc      |
| 7     | y       | 7     | yy      |
| NULL  | NULL    | 9     | pp      |
+-------+---------+-------+---------+--+

full outer join 操作

select * from a full outer join b on a.id=b.id;

+-------+---------+-------+---------+--+
| a.id  | a.name  | b.id  | b.name  |
+-------+---------+-------+---------+--+
| 1     | a       | NULL  | NULL    |
| 2     | b       | 2     | bb      |
| 3     | c       | 3     | cc      |
| 4     | d       | NULL  | NULL    |
| 7     | y       | 7     | yy      |
| 8     | u       | NULL  | NULL    |
| NULL  | NULL    | 9     | pp      |
+-------+---------+-------+---------+--+

left semi 操作

select * from a left semi join b on a.id=b.id;

+-------+---------+--+
| a.id  | a.name  |
+-------+---------+--+
| 2     | b       |
| 3     | c       |
| 7     | y       |
+-------+---------+--+

select * from b left semi join a on a.id=b.id;

+-------+---------+--+
| b.id  | b.name  |
+-------+---------+--+
| 2     | bb      |
| 3     | cc      |
| 7     | yy      |
+-------+---------+--+