如何计算 sql 同一列中前一行与当前行之间的百分比变化？

Question

这是我的查询，但百分比变化列是错误的

select 
     year(ref_date), trade, trade_category, totalvalue, 
round(((totalvalue) - (LAG(totalvalue) OVER(ORDER BY year(ref_date))*100/ totalvalue)),0) percent_change 

from 
     data.services 
where 
    trade_category != "Commercial services, total" 
and 
    trade_category = "Financial services" 
group by 
     year(ref_date) 
order by 
      year(ref_date), totalvalue;

[下面是结果，但百分比变化的计算有效][1] [1]：https://i.stack.imgur.com/eoIcT.png

Answer 1

tghe window function 的形式必须保留你不能添加/total到它

LAG (column) OVER (PARTITION BY col2 ORDER BY col3)

在手册中阅读更多关于 window function的信息

select 
     year(year_date), type, type_category, total, 
round(((100.00 * total) - (LAG(total) OVER(ORDER BY year_date)/ total)),0) percent_change 

from 
     kev.trade 
where 
     type = "science" 
and 
     type_category = "data services" 
group by 
     year_date, type_category 
order by 
      year_date, total;