計數產品不止一次訂購

Question

我需要獲得多次訂購的產品的數量並且僅由客戶訂購一次。我可能正在看這個錯誤的方式，請原諒我，如果SQL看起來很愚蠢或什麼的。

SELECT ActualOrder.Sku, 
COUNT(DISTINCT Email) AS UniqueCustomer, 
COUNT(DISTINCT OrderNumber) AS NumOrders, 
COUNT(Reordered.Sku) AS NumReordered, 
COUNT(OrderedOnce.Sku) AS NumOrderedOnce 
FROM ActualOrder 
LEFT JOIN (SELECT Sku FROM ActualOrder GROUP BY Email HAVING COUNT(DISTINCT OrderNumber) > 1) AS Reordered ON ActualOrder.Sku = Reordered.Sku 
LEFT JOIN (SELECT Sku FROM ActualOrder GROUP BY Email HAVING COUNT(DISTINCT OrderNumber) = 1) AS OrderedOnce ON ActualOrder.Sku = OrderedOnce.Sku 
GROUP BY ActualOrder.Sku 

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從正從子查詢計數的吳宇森的想法，我想出了這個代碼，它實際上做的工作，但有點嵌套。也許你們可以幫助我提高效率或縮短時間。再次感謝所有的幫助！

SELECT ActualOrder.Sku, 
COUNT(DISTINCT Email) AS UniqueCustomer, 
COUNT(DISTINCT OrderNumber) AS NumOrders, 
NumReordered, 
NumOrderedOnce 
FROM ActualOrder 
LEFT JOIN (SELECT Sku, SUM(IF(NumCustomerOrders>1,1,0)) AS NumReordered, SUM(IF(NumCustomerOrders=1,1,0)) AS NumOrderedOnce 
    FROM (SELECT Sku, Email, COUNT(DISTINCT OrderNumber) AS NumCustomerOrders 
     FROM ActualOrder GROUP BY Sku, Email) 
    AS Orders GROUP BY Sku) AS OrderCount ON ActualOrder.Sku = OrderCount.Sku 
GROUP BY ActualOrder.Sku 

Answer 1

你可以指望的訂單上subquery

SELECT ActualOrder.Sku, 
     Reordered.NumReordered, 
     OrderedOnce.NumOrderedOnce 
     COUNT(DISTINCT Email) AS UniqueCustomer, 
     COUNT(DISTINCT OrderNumber) AS NumOrders 
FROM ActualOrder 
     LEFT JOIN 
     (
      SELECT Sku, COUNT(*) NumReordered 
      FROM ActualOrder 
      GROUP BY Email 
      HAVING COUNT(*) > 1 
     ) AS Reordered ON ActualOrder.Sku = Reordered.Sku 
     LEFT JOIN 
     (
      SELECT Sku, COUNT(*) NumOrderedOnce 
      FROM ActualOrder 
      GROUP BY Email 
      HAVING COUNT(*) = 1 
     ) AS OrderedOnce ON ActualOrder.Sku = OrderedOnce.Sku 
GROUP BY ActualOrder.Sku, 
      Reordered.NumReordered, 
      OrderedOnce.NumOrderedOnce