已选择12行。
over函数的空括号表示该记录集的所有记录都应该被列入统计的范围,如果使用了partition by则先分区,再依次统计各个分区。
二、RATIO_TO_REPORT函数:
报表函数特(窗口函数)特别适合于报表中需要同时显示详细数据和统计数据的情况。例如在销售报告中经常会出现这样的需求:列出上一年度每个月的销售总额、年底销售额以及每个月的销售额占全年总销售额的比例:
方法①:
代码如下:
select all_sales.*,
100 * round(cust_sales / region_sales, 2) || '%' Percent
from (select o.cust_nbr customer,
o.region_id region,
sum(o.tot_sales) cust_sales,
sum(sum(o.tot_sales)) over(partition by o.region_id) region_sales
from orders_tmp o
where o.year = 2001
group by o.region_id, o.cust_nbr) all_sales
where all_sales.cust_sales > all_sales.region_sales * 0.2;
100 * round(cust_sales / region_sales, 2) || '%' Percent
from (select o.cust_nbr customer,
o.region_id region,
sum(o.tot_sales) cust_sales,
sum(sum(o.tot_sales)) over(partition by o.region_id) region_sales
from orders_tmp o
where o.year = 2001
group by o.region_id, o.cust_nbr) all_sales
where all_sales.cust_sales > all_sales.region_sales * 0.2;
这是一种笨方法也是最易懂的方法。
方法②:
代码如下:
select region_id, salesperson_id,
sum(tot_sales) sp_sales,
round(sum(tot_sales) / sum(sum(tot_sales))
over (partition by region_id), 2) percent_of_region
from orders
where year = 2001
group by region_id, salesperson_id
order by region_id, salesperson_id;
sum(tot_sales) sp_sales,
round(sum(tot_sales) / sum(sum(tot_sales))
over (partition by region_id), 2) percent_of_region
from orders
where year = 2001
group by region_id, salesperson_id
order by region_id, salesperson_id;
方法③
代码如下:
select region_id, salesperson_id,
sum(tot_sales) sp_sales,
round(ratio_to_report(sum(tot_sales))
over (partition by region_id), 2) sp_ratio
from orders
where year = 2001
group by region_id, salesperson_id
order by region_id, salesperson_id;
sum(tot_sales) sp_sales,
round(ratio_to_report(sum(tot_sales))
over (partition by region_id), 2) sp_ratio
from orders
where year = 2001
group by region_id, salesperson_id
order by region_id, salesperson_id;
Oracle提供的Ratio_to_report函数允许我们计算每条记录在其对应记录集或其子集中所占的比例。
以上就是Oracle报表函数用法的全部内容,希望能给大家一个参考,也希望大家多多支持。