开窗积累之学习更新版

1. 开窗使用1之 count range between current row and current row
   将相同排序字段的值进行函数计算

select
    sku_id,
    substr(create_date,1,7) date_month,
    order_id,
    create_date,
    sku_num*price,
    sum(sku_num*price) over (partition by sku_id order by substr(create_date,1,7) range between current row and current row ) month_num_n
    --dense_rank() over (partition by sku_id order by substr(create_date,1,7) )
from order_detail