错误：PostgreSQL中“ from”处或附近的语法错误

Question

我正在做一些RFM模型，被困在这里：

select "customer_id" as a, rfm_recency*100 + rfm_frequency*10 as rfm_combined
from
(select a, 
       ntile(4) over (order by recency) as rfm_recency,
       ntile(4) over (order by frequency) as rfm_frequency) x
from
(select a,
       max("purchase_date") as recency,
       count(*) as frequency
from "customer") y

  

“ from”处或附近的语法错误

Answer 1

我找到了答案：

select "customer_id" as a, rfm_recency*100 + rfm_frequency*10 as rfm_combined
from
(select a, 
       ntile(4) over (order by recency) as rfm_recency,
       ntile(4) over (order by frequency) as rfm_frequency
from
(select a,
       max("purchase_date") as recency,
       count(*) as frequency
from "customer") x)y