從多列的 SUM() 中選擇並加入 postgreSQL

Question

我有一個名為 DETAILS 的表，它有 5 個數字列 DETAILS(id, key2, key3, num1, num2, num3, num4, num5)。 id、key2 和 key3 的組合是主鍵。 每個 id 可能有多行。

我的要求是獲取按 id 分組的每列的前 10 個 SUM 值，如下所示。

select   id
        ,sum(num1) val1
 from details   
group by id
order by sum(num1) desc nulls last
limit 10;

select   id
        ,sum(num2) val2
 from details  
group by id
order by sum(num2) desc nulls last
limit 10;

select   id
        ,sum(num3) val3
 from details   
group by id
order by sum(num3) desc nulls last
limit 10;

select   id
        ,sum(num4) val4
 from details   
group by id
order by sum(num4) desc nulls last
limit 10;

select   id
        ,sum(num5) val5
 from details
group by id
order by sum(num5) desc nulls last
limit 10;

我需要根據下面的 id 組合上述結果

id, sum(num1), sum(num2), sum(num3), sum(num4), sum(num5)

假設第一個查詢返回

[{id: 1, val1: 50}, {id: 2, val1: 60}, {id: 3, val1: 70}]

第二個查詢返回

[{id: 3, val2: 150}, {id: 4, val2: 160}, {id: 3, val2: 170}]

結果應該是

[
{id: 1, val1: 50, val2: null}, 
{id: 2, val1: 60, val2: null}, 
{id: 3, val1: 70, val2: 150},
{id: 4, val1: null, val2: 160},
{id: 5, val1: null, val2: 170},
]

這可以通過使用 join 或其他方式的單個查詢實現嗎？ 如果是這樣，我如何通過優化查詢來實現這一點？

Answer 1

我認為您需要對所有 5 個查詢進行 FULL OUTER JOIN：

with
  cte1 as (
    select id, sum(num1) val1 from details   
    group by id
    order by sum(num1) desc nulls last limit 10
  ),
  cte2 as (
    select id, sum(num2) val2 from details   
    group by id
    order by sum(num2) desc nulls last limit 10
  ),  
  cte3 as (
    select id, sum(num3) val3 from details   
    group by id
    order by sum(num3) desc nulls last limit 10
  ),  
  cte4 as (
    select id, sum(num4) val4 from details   
    group by id
    order by sum(num4) desc nulls last limit 10
  ),  
  cte5 as (
    select id, sum(num5) val5 from details   
    group by id
    order by sum(num5) desc nulls last limit 10
  )
select coalesce(c1.id, c2.id, c3.id, c4.id, c5.id) id,
       c1.val1, c2.val2, c3.val3, c4.val4, c5.val5
from cte1 c1
full outer join cte2 c2 on c2.id = c1.id
full outer join cte3 c3 on c3.id = c2.id
full outer join cte4 c4 on c4.id = c3.id
full outer join cte5 c5 on c5.id = c4.id