解释一条SQL语句

2007-06-29 04:36:42 201 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

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基于 MATLAB 的综合能源系统建模案例电平衡约束：P_{gt}(t)+P_{grid}(t)-P_{eb}(t)-P_{load}(t)=0，其中 P_{grid}(t) 为与外部电网的交互功率（正表示购电，负表示售电）。- 电锅炉的热输出功率 Q_{eb} 与输入电功率 P_{eb} 的关系为：Q_{eb}=\eta_{eb}\times P_{eb}，其中 \eta_{eb} 为电锅炉的热效率。- 燃气轮机的余热回收功率 Q_{gt} 与发电功率也存在一定关系，例如：Q_{gt}=c\times P_{gt}，c 为余热回收比例系数。阅读详情

CREATE Procedure CMRC_CustomerAlsoBought
(
@ProductID int
)
As

/* We want to take the top 5 products contained in
the orders where someone has purchased the given Product */
SELECT TOP 5
CMRC_OrderDetails.ProductID,
CMRC_Products.ModelName,
SUM(CMRC_OrderDetails.Quantity) as TotalNum

FROM
CMRC_OrderDetails
INNER JOIN CMRC_Products ON CMRC_OrderDetails.ProductID = CMRC_Products.ProductID

WHERE OrderID IN
(
/* This inner query should retrieve all orders that have contained the productID */
SELECT DISTINCT OrderID
FROM CMRC_OrderDetails
WHERE ProductID = @ProductID
)
AND CMRC_OrderDetails.ProductID != @ProductID

GROUP BY CMRC_OrderDetails.ProductID, CMRC_Products.ModelName

ORDER BY TotalNum DESC

GO

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