C# '在需要条件的上下文中指定的非布尔类型的表达式，当日期介于

我正在创建一个sql查询，我想制作损益表 但我的查询中有一个错误：

'在需要条件的上下文中指定的非布尔类型的表达式，靠近'，'

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如何修复此问题？

只需识别您的SQL命令，就可以看到其中有错误，请看：

SELECT 
  CAST(Pay_invoice_details.Barcode AS INT), 
  SUM(CAST(Pay_invoice_details.Total_items_price AS INT)) AS 'Total Payes', 
  SUM(CAST(Pay_invoice_details.Quantity AS INT) * CAST(Buy_invoice_details.Purchase_price AS INT)) AS 'Total Purchases', 
  CAST(Pay_invoice_details.Invoice_date AS DATE), 
  CAST(Buy_invoice_details.Barcode AS INT), 
  CAST(Buy_invoice_details.Invoice_date AS DATE), 
  SUM(CAST(Payouts_details.Total_amount AS INT)) AS 'Total Payouts' 
FROM 
  Pay_invoice_details,
  Buy_invoice_details,
  Payouts_details 
where 
  Pay_invoice_details.Barcode=Buy_invoice_details.Barcode and 
  Pay_invoice_details.Invoice_date, 
  Buy_invoice_details.Invoice_date, 
  Payouts_details.Invoice_date 
    between '" + from.Value.ToString("yyyy-MM-dd") + "' and'" + to.Value.ToString("yyyy-MM-dd") + "'

在WHERE子句中，您使用了一个包含3列的列表来比较日期范围（使用BETWEEN）。这不是它的工作原理。如果你的意图是考虑第一列，如果它是NULL，考虑第二列，如果它也是NULL，考虑第三，你应该使用CueSeCe函数。就像这样：

(...)
where 
  Pay_invoice_details.Barcode=Buy_invoice_details.Barcode and 
  COALESCE(
    Pay_invoice_details.Invoice_date, 
    Buy_invoice_details.Invoice_date, 
    Payouts_details.Invoice_date
  ) between '" + from.Value.ToString("yyyy-MM-dd") + "' and'" + to.Value.ToString("yyyy-MM-dd") + "'

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哦，看起来像是请研究如何正确使用查询中的参数在您的查询中确定。这是无效的。为什么不先在SQLServer控制台中完善一下呢。然后插入，网络？

(...)
where 
  Pay_invoice_details.Barcode=Buy_invoice_details.Barcode and 
  COALESCE(
    Pay_invoice_details.Invoice_date, 
    Buy_invoice_details.Invoice_date, 
    Payouts_details.Invoice_date
  ) between '" + from.Value.ToString("yyyy-MM-dd") + "' and'" + to.Value.ToString("yyyy-MM-dd") + "'