Oracle CROSS JOIN example

最新推荐文章于 2024-06-17 21:28:28 发布

原创最新推荐文章于 2024-06-17 21:28:28 发布 · 57 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#Oracle #SQL

Oracle 专栏收录该内容

68 篇文章

订阅专栏

本文介绍了一种使用SQL实现笛卡尔积的方法，并通过批量插入数据的方式填充销售预测表。具体实现上，通过跨表连接的方式生成了学校、地区与时间维度的所有组合。

笛卡尔积：


insert into t_sales_forecast
select SALES_FORECAST_SEQUENCE.nextval as id,basic.* from 
(
select school_id,district_id,year_table.year,month_table.month ,500 as or_forcast,1000 as re_forcast,sysdate as update_date,'1' as user_id,sysdate as insert_date
from v_school_district
cross join 
(
select level as year from dual  where level>2006 connect by level<2012
) year_table
cross join 
(
select lpad(level,2,0) month from dual connect by level <13 
) month_table
order by school_id,district_id,year_table.year,month_table.month 
) basic