Question

我正在尝试将一些客户订单数据汇总到一个表中进行分析。数据是客户订购的产品数量，然后尝试确定订单是小订单，中订单还是大订单，然后通过OrderSize确定他们购买的产品总数和订单成本。

小订单 - 1 - 2个产品
中等订单 - 3-4产品
大订单 - ＆gt; = 5个产品

以下是数据：

CustomerID  OrderID   OrderSize OrderTotal
1           800       1         $20
2           801       1         $10
3           802       4         $85
1           803       1         $30
2           804       8         $120
3           805       1         $40

这是我试图构建的表格（更容易发布图像）： Table Screenshot

我可以运行这样的更新查询来填充表格：

- 建立表格 -

CREATE TABLE Customers (
    CustomerID varchar(10) PRIMARY KEY,
    SmallOrderCount int,
    SmallOrderProducts int,
    SmallOrderTotal money,
    MedOrderCount int,
    MedOrderProducts int,
    MedOrderTotal money,
    LargeOrderCount int,
    LargeOrderProducts int,
    LargeOrderTotal money
);

- 插入唯一客户 -

INSERT INTO Customers
SELECT CustomerID FROM Orders GROUP BY CustomerID;

- 更新以填充订单信息 -

UPDATE Customers
SET SmallOrderCount = (SELECT count(*) FROM Orders WHERE OrderSize BETWEEN 1 AND 2 AND Orders.CustomerID = Customers.CustomerID);

UPDATE Customers 
SET SmallOrderProducts = (SELECT sum(OrderSize) FROM Orders WHERE OrderSize BETWEEN 1 AND 2 AND Orders.CustomerID = Customers.CustomerID);

UPDATE Customers 
SET SmallOrderTotal = (SELECT sum(OrderTotal) FROM Orders WHERE OrderSize BETWEEN 1 AND 2 AND Orders.CustomerID = Customers.CustomerID);

然后我可以为剩余的6列重复此操作。

但是，这似乎很多工作。有没有办法使用可能较少工作的子查询填充我的Customer表？或者我的方法是最直接的？

Answer 1

一个insert应该足够了：

INSERT INTO Customers(CustomerID,SmallOrderCount,SmallOrderProducts,
   SmallOrderTotal)     
SELECT a.CustomerID, COUNT(a.*) as cnt, sum(a.OrderSize) as OrderSize,
    sum(a.OrderTotal) as OrderTotal 
   FROM Orders a
   WHERE a.OrderSize BETWEEN 1 AND 2 
   GROUP BY a.CustomerID

上述查询将仅插入订单大小介于1和2之间的客户。如果您还需要插入其他客户，则可以使用：

INSERT INTO Customers(CustomerID,SmallOrderCount,SmallOrderProducts,
   SmallOrderTotal)     
SELECT a.CustomerID, 
COUNT(CASE WHEN  a.OrderSize BETWEEN 1 AND 2  THEN 1 END) as cnt, 
sum(CASE WHEN  a.OrderSize BETWEEN 1 AND 2  THEN a.OrderSize ELSE 0 END) as OrderSize,
sum(CASE WHEN  a.OrderSize BETWEEN 1 AND 2  THEN a.OrderTotal ELSE 0 END ) as OrderTotal 
FROM Orders a
GROUP BY a.CustomerID

Answer 2

您可以使用CASE语句在一个INSERT命令中执行所有：

INSERT INTO Customers
SELECT CustomerID
      ,sum(CASE WHEN OrderSize BETWEEN 1 AND 2 THEN 1 ELSE 0 END) AS SmallOrderCount
      ,sum(CASE WHEN OrderSize BETWEEN 1 AND 2 THEN OrderSize ELSE 0 END) AS SmallOrderProducts
      ,sum(CASE WHEN OrderSize BETWEEN 1 AND 2 THEN OrderTotal ELSE 0 END) AS SmallOrderTotal
      ,sum(CASE WHEN OrderSize BETWEEN 3 AND 4 THEN 1 ELSE 0 END) AS MedOrderCount
      ,sum(CASE WHEN OrderSize BETWEEN 3 AND 4 THEN OrderSize ELSE 0 END) AS MedOrderProducts
      ,sum(CASE WHEN OrderSize BETWEEN 3 AND 4 THEN OrderTotal ELSE 0 END) AS MedOrderTotal
      ,sum(CASE WHEN OrderSize > 4 THEN 1 ELSE 0 END) AS LargeOrderCount
      ,sum(CASE WHEN OrderSize > 4 THEN OrderSize ELSE 0 END) AS LargeOrderProducts
      ,sum(CASE WHEN OrderSize > 4 THEN OrderTotal ELSE 0 END) AS LargeOrderTotal
FROM   Orders
GROUP  BY CustomerID;

请参阅此working demo for the full query on data.SE。

Answer 3

我只创建一个查询（可以用作视图），而不是一个全新的持久表。

WITH cteOrders AS (
    SELECT CustomerID,
        CASE WHEN OrderSize BETWEEN 1 AND 2 THEN OrderSize END SmallOrderProducts,
        CASE WHEN OrderSize BETWEEN 1 AND 2 THEN OrderTotal END SmallOrderTotal,
        CASE WHEN OrderSize BETWEEN 3 AND 4 THEN OrderSize END MediumOrderProducts,
        CASE WHEN OrderSize BETWEEN 3 AND 4 THEN OrderTotal END MediumOrderTotal,
        CASE WHEN OrderSize > 4 THEN OrderSize END LargeOrderProducts,
        CASE WHEN OrderSize > 4 THEN OrderTotal END LargeOrderTotal
    FROM Orders
)
SELECT CustomerID,
        COUNT(SmallOrderProducts) SmallOrderCount,
        COALESCE(SUM(SmallOrderProducts), 0) SmallOrderProducts,
        COALESCE(SUM(SmallOrderTotal), 0) SmallOrderTotal,
        COUNT(MediumOrderProducts) MediumOrderCount,
        COALESCE(SUM(MediumOrderProducts), 0) MediumOrderProducts,
        COALESCE(SUM(MediumOrderTotal), 0) MediumOrderTotal,
        COUNT(LargeOrderProducts) LargeOrderCount,
        COALESCE(SUM(LargeOrderProducts), 0) LargeOrderProducts,
        COALESCE(SUM(LargeOrderTotal), 0) LargeOrderTotal
    FROM cteOrders
    GROUP BY CustomerID

Answer 4

您可以使用单个INSERT INTO SELECT语句

来完成此操作

INSERT INTO Customers
SELECT * ,
 (SELECT count(*) FROM Orders WHERE OrderSize BETWEEN 1 AND 2 AND Orders.CustomerID = CustomerID),
 (SELECT sum(OrderSize) FROM Orders WHERE OrderSize BETWEEN 1 AND 2 AND Orders.CustomerID  = CustomerID)

 FROM CUSTOMERS

聚合数据的最佳方式 - 更新查询或子查询？

4 个答案: