SQL - 选择不同的列而不排除行

Question

我正在运行一个查询，该查询在某个日期范围内按类别或子类别汇总销售信息。我被要求为其添加预算信息，以显示该查询提取的信息的报告。

SELECT
    DATE_FORMAT(B.TxnDate, "%Y-%m") AS FormattedTxnDate,
    SUM(B.Quantity) AS QuantitySum,
    SUM(B.Quantity * B.Amount) AS Revenue,
    SUM(CASE WHEN B.AverageCost = 0 THEN (B.Quantity * C.PurchaseCost) ELSE (B.Quantity * 
    B.AverageCost) END) AS COGS,
    A.CustomerRefFullName,
    SUM(D.Budget_2018) AS Budget,
    D.Brand, D.Category, D.Subcategory, D.ProductManager, C.VendorRefFullName
FROM
    qb_invoice_info A, qb_invoice_line_info B, qb_item_info C, qb_item_group D
WHERE
    A.TxnID = B.TxnID
AND
    B.Item_ListID = C.ListID
AND
    C.Parent_ListID = D.ListID
AND
    (C.Type = "Inventory" OR C.Type = "InventoryAssembly")
AND
    B.TxnDate BETWEEN ? AND ?
GROUP
    BY D.Category, YEAR(B.TxnDate), QUARTER(B.TxnDate)
ORDER
    BY D.Category ASC, YEAR(B.TxnDate) ASC, QUARTER(B.TxnDate) ASC

每个子类别都有自己的预算金额。问题是某些子类别共享所有相同的信息，除了它们的唯一ID。 qb_item_group表中的一些记录可能如下所示。

qb_item_group
id | Category | Subcategory | Budget
------------------------------------
1A | Lights   | DMX         | 4000
1B | Lights   | DMX         | 4000
1C | Lights   | DMX         | 4000
2A | Lights   | Flash       | 5000
3A | Lights   | Bulbs       | 1000

在这种情况下，灯的总预算将为10,000，因为我们忽略了两个DMX预算。我今天早些时候尝试了SUM(DISTINCT D.Budget_2018 AS Budget，但它失败了，因为它只是添加了独特的预算值。我如何调整上面的查询，以便我可以按类别或子类别检索所有销售记录，但仍然得到总预算，即父类别下所有唯一子类别的总和？

Answer 1

SELECT  
  DATE_FORMAT(B.TxnDate, "%Y-%m")      AS FormattedTxnDate, 
  SUM(B.Quantity)                      AS QuantitySum,
  SUM(B.Quantity * B.Amount) AS Revenue,
  SUM(
    CASE 
      WHEN B.AverageCost = 0 THEN (B.Quantity * C.PurchaseCost) 
      ELSE (B.Quantity * B.AverageCost) 
    END
  )                                    AS COGS, 
  A.CustomerRefFullName, 
  COALESCE(category_budgets.budget, 0) AS budget,
  D.Brand,
  D.Category,
  D.Subcategory,
  D.ProductManager,
  C.VendorRefFullName
FROM 
  qb_invoice_info A, 
  qb_invoice_line_info B, 
  qb_item_info C, 
  qb_item_group D
LEFT JOIN
(
  SELECT
    a.category,
    SUM(a.budget) as budget
  FROM
  (
    SELECT DISTINCT
      category
      budget
    FROM 
      budgets
  ) a
) category_budgets
ON
  category_budgets.category = D.category
WHERE 
  A.TxnID = B.TxnID
AND 
  B.Item_ListID = C.ListID
AND 
  C.Parent_ListID = D.ListID
AND 
  (C.Type = "Inventory" OR C.Type = "InventoryAssembly")
AND 
  B.TxnDate BETWEEN ? AND ?
GROUP BY 
  D.Category, YEAR(B.TxnDate), QUARTER(B.TxnDate)
ORDER BY 
  D.Category ASC, YEAR(B.TxnDate) ASC, QUARTER(B.TxnDate) ASC
;

您可以使用不同类别和预算的总和来保持联接。这将为您提供所需的所有输出行，但也会为预算表中没有条目的类别提供$ 0预算。祝好运！