示例数据
为便于理解，本文为您提供源数据，基于源数据提供相关示例。创建表sale_detail和sale_detail_sj，并添加数据，命令示例如下：
--创建一张分区表sale_detail。
create table if not exists sale_detail
(
shop_name string,
customer_id string,
total_price double
)
partitioned by (sale_date string, region string);
create table if not exists sale_detail_sj
(
shop_name string,
customer_id string,
total_price double
)
partitioned by (sale_date string, region string);
--向源表增加分区。
alter table sale_detail add partition (sale_date='2013', region='china');
alter table sale_detail_sj add partition (sale_date='2013', region='china');
--向源表追加数据。
insert into sale_detail partition (sale_date='2013', region='china') values ('s1','c1',100.1),('s2','c2',100.2),('s3','c3',100.3);
insert into sale_detail_sj partition (sale_date='2013', region='china') values ('s1','c1',100.1),('s2','c2',100.2),('s5','c2',100.2),('s2','c2',100.2);
查询表sale_detail和sale_detail_sj中的数据，命令示例如下：
select * from sale_detail;
--返回结果。
+------------+-------------+-------------+------------+------------+
| shop_name | customer_id | total_price | sale_date | region |
+------------+-------------+-------------+------------+------------+
| s1 | c1 | 100.1 | 2013 | china |
| s2 | c2 | 100.2 | 2013 | china |
| s3 | c3 | 100.3 | 2013 | china |
+------------+-------------+-------------+------------+------------+
select * from sale_detail_sj;
--返回结果。
+------------+-------------+-------------+------------+------------+
| shop_name | customer_id | total_price | sale_date | region |
+------------+-------------+-------------+------------+------------+
| s1 | c1 | 100.1 | 2013 | china |
| s2 | c2 | 100.2 | 2013 | china |
| s5 | c2 | 100.2 | 2013 | china |
| s2 | c2 | 100.2 | 2013 | china |
+------------+-------------+-------------+------------+------------+
使用示例
对表sale_detail和sale_detail_sj执行join操作，满足sale_detail_sj中的total_price小于sale_detail中的total_price或sale_detail_sj中的total_price与sale_detail中的total_price之和小于500的条件，命令示例如下：
select /*+ mapjoin(a) */
a.shop_name,
a.total_price,
b.total_price
from sale_detail_sj a join sale_detail b
on a.total_price < b.total_price or a.total_price + b.total_price < 500;
返回结果如下：
+-----------+-------------+--------------+
| shop_name | total_price | total_price2 |
+-----------+-------------+--------------+
| s1 | 100.1 | 100.1 |
| s2 | 100.2 | 100.1 |
| s5 | 100.2 | 100.1 |
| s2 | 100.2 | 100.1 |
| s1 | 100.1 | 100.2 |
| s2 | 100.2 | 100.2 |
| s5 | 100.2 | 100.2 |
| s2 | 100.2 | 100.2 |
| s1 | 100.1 | 100.3 |
| s2 | 100.2 | 100.3 |
| s5 | 100.2 | 100.3 |
| s2 | 100.2 | 100.3 |
+-----------+-------------+--------------+
mapjoin多个小表示例，请参见如何用MAPJOIN缓存多张小表？。
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