嵌套查詢返回值

Question

我有一個表order_details這樣

id | SKU | quantity_purchased | discount_price 
--------------------------------------------------- 
1 | abc | 1     |  10.0 
2 | abc | 90    |  00 
2 | abc | 9     |  00 
3 | xyz | 1     |  50.0 
3 | xyz | 2     |  50.0 
4 | xyz | 100    |  00 
4 | xyz | 100    |  00 
----------------------------------------------- 

我的查詢是

select 
(select sum(quantity_purchased) from order_details where discount_price > 0.00) as qty_discount, 
(select sum(quantity_purchased) from order_details where discount_price = 0.00)as qty_original, 
sku 
from order_details 
GROUP BY sku 

我需要的結果是

SKU | quantity_original | quantity_discount 
--------------------------------------------------- 
abc | 1     |  99 
xyz | 3     |  200 
----------------------------------------------- 

也就是說，我需要兩列計算後相同sku，

我無法建立的邏輯，我在嵌套查詢使用GROUP BY試過，但它不工作... 任何幫助，高度讚賞.. 感謝

UPDATE： 嘗試通過做這不過還是失敗，

select 
(select sum(quantity_purchased) from order_details where discount_price > 0.00) as qty_discount, 
(select sum(quantity_purchased) from order_details where discount_price = 0.00)as qty_original, 
sku 
from order_details 
where sku = (select distinct sku from order_details) 
GROUP BY sku 

Answer 1

您可以使用conditional aggregation此：

select sku, 
     sum(case when discount_price != 0 then quantity_purchased 
       else 0 
      end) quantity_original, 
     sum(case when discount_price = 0 then quantity_purchased 
       else 0 
      end) quantity_discount 
from order_details 
group by sku 

• SQL Fiddle Demo

---

Results: 

| SKU | quantity_original | quantity_discount | 
|-----|-------------------|-------------------| 
| abc |     1 |    99 | 
| xyz |     3 |    200 |