如何在外部查询 SQL 中聚合不同的 CTE

Question

i am trying to join two ctes to get the difference in performance of different countries and group on id here is my example

every campaign can be done in different countries, so how can i group by at the end to have 1 row per campaign id?

CTE 1: (planned)

select 
country
, campaign_id 
, sum(sales) as planned_sales
from table x
group by 1,2

CTE 2: (Actual)

select 
country
, campaign_id
, sum(sales) as actual_sales
from table y
group by 1,2 

outer select

select 
country,
planned_sales,
actual_sales
planned - actual as diff 
from cte1
join cte2 
on campaign_id = campaign_id 

Answer 1

This should do it:

select 
cte1.campaign_id,
sum(cte1.planned_sales),
sum(cte2.actual_sales)
sum(cte1.planned_sales) - sum(cte2.actual_sales) as diff 
from cte1
join cte2 
on cte1.campaign_id = cte2.campaign_id and cte1.country = cte2.country
group by 1

Answer 2

I would suggest using full join , so all data is included in both tables, not just data in one or the other. Your query is basically correct but it needs a group by .

select campaign_id,
       sum(cte1.planned_sales) as planned_sales
       sum(cte2.actual_sales) as actual_sales,
       (coalesce(sum(cte1.planned_sales), 0) - 
        coalesce(sum(cte2.actual_sales), 0)
       ) as diff
from cte1 full join
     cte2 
     using (campaign_id, country) 
group by campaign_id;

That said, there is no reason why the CTEs should aggregate by both campaign and country. They could just aggregate by campaign id -- simplifying the query and improving performance.