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爲了簡化事情,可以說我有一個模型StockIOLog。怎麼寫先進的Django ORM查詢
class StockIOLog(models.Model):
pid = models.IntegerField()
name= models.CharField(max_length=50)
type= models.IntegerField()
stock = models.IntegerField()
它包含了以下數據:
pid | name | batch | type | quantity
------------------------------------------------
1 | Napa | AB | 0 | 100
------------------------------------------------
1 | Napa | AA | 0 | 100
------------------------------------------------
2 | Amod | AA | 0 | 100
------------------------------------------------
2 | Amod | CA | 0 | 100
------------------------------------------------
1 | Napa | AB | 1 | 10
------------------------------------------------
1 | Napa | AB | 1 | 5
------------------------------------------------
1 | Napa | AA | 1 | 20
------------------------------------------------
2 | Amod | AA | 1 | 10
------------------------------------------------
2 | Amod | AA | 1 | 50
------------------------------------------------
2 | Amod | CA | 1 | 5
------------------------------------------------
2 | Amod | CA | 1 | 15
類型0意味着購買產品,1型是指產品的被消耗,現在我想計算分批每一個產品的庫存總量。
通過運行下面的SQL查詢
SELECT pid, name, batch, SUM(in) - SUM(out) as stock FROM (
SELECT pid, name, type SUM(quantity) as in, 0 as out from `qset` WHERE type=0 GROUP BY pid,type,batch as a
UNION
SELECT pid, name, type 0 as in, SUM(quantity) as out from `qset` WHERE type=1 GROUP BY pid,type,batch as b
) ac table_a
我獲得以下查詢集
pid | name | batch | stock
-----------------------------------
1 | Napa | AB | 85
-----------------------------------
1 | Napa | AA | 80
-----------------------------------
2 | Amod | AA | 40
-----------------------------------
2 | Amod | CA | 80
如何做類似的事情在Django ORM?
得到字典
purchased
和consumed
這是很難理解的SQL查詢的問題。你能解釋一下這個場景嗎? –@ Md.Al-Amin更簡短地更新了問題 –