C# 这更自然。我们匈牙利人给了世界这么多。。。看到SQL，我感到非常自豪！；） SELECT fCustomerID, ISNULL( (SELECT SUM(payinv.fAmount) AS Expr1

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这更自然。我们匈牙利人给了世界这么多。。。看到SQL，我感到非常自豪！；）

SELECT fCustomerID,
       ISNULL(
                (SELECT SUM(payinv.fAmount) AS Expr1
                 FROM dbo.tARPayment AS pay
                 INNER JOIN dbo.tARPaymentInvoice AS payinv ON pay.fPaymentID = payinv.fPaymentID
                 INNER JOIN dbo.tARInvoice AS inv ON payinv.fInvoiceID = inv.fARInvoiceID
                 WHERE (pay.fIsPosted = CASE pay.fPaymentType WHEN 'CM' THEN 0 WHEN 'EPD' THEN 0 ELSE 1 END)
                   AND (inv.fCustomerID <> dbo.tARCustomer.fCustomerID)
                   AND (pay.fCustomerID = dbo.tARCustomer.fCustomerID)), 0)
FROM dbo.tARCustomer
GROUP BY fCustomerID

public partial class tARPayment 
{
    #region Constructor

    /// <summary>
    /// Initializes a new instance of the <see cref="tARPayment"/> class.
    /// </summary>
    public tARPayment()
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="tARPayment"/> class.
    /// </summary>
    /// <param name="fPaymentID">The fPaymentID of guid type.</param>
    public tARPayment(System.Guid fPaymentID)
    {
        this.ID = fPaymentID;
    }
    #endregion

    #region Properties

    /// <summary>
    /// Gets or sets payment id.
    /// </summary> 
    public virtual System.Guid fPaymentID { get; set; }

    /// <summary>
    /// Gets or sets fCustomerID.
    /// </summary> 
    public virtual System.Guid fCustomerID { get; set; }

    /// <summary>
    /// Gets or sets check number.
    /// </summary> 
    public virtual string fCheckNumber { get; set; }

    /// <summary>
    /// Gets or sets amount.
    /// </summary> 
    public virtual decimal fAmount { get; set; }       

    /// <summary>
    /// Gets or sets customer detail.
    /// </summary> 
    public virtual tARCustomer Customer { get; set; }

    public virtual IList<tARPaymentInvoice> PaymentInvoices { get; set; }        

    #endregion

    #region Methods
    /// <summary>
    /// partial class for payment.
    /// </summary>
    /// <returns>The method get code.</returns>
    public override int GetHashCode()
    {
        return ID.GetHashCode();
    }
    #endregion
}

public partial class tARInvoice 
{
    #region Constructor
    /// <summary>
    /// Initializes a new instance of the <see cref="tARInvoice"/> class.
    /// </summary>
    public tARInvoice()
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="tARInvoice"/> class.
    /// </summary>
    /// <param name="fARInvoiceID">The fARInvoiceID.</param>
    public tARInvoice(System.Guid fARInvoiceID)
    {
        this.ID = fARInvoiceID;
    }

    #endregion

    #region Properties
    /// <summary>
    /// Gets or sets fARInvoiceID.
    /// </summary> 
    public virtual Guid fARInvoiceID { get; set; }

    /// <summary>
    /// Gets or sets fCustomerID.
    /// </summary> 
    public virtual Guid fCustomerID { get; set; }


    /// <summary>
    /// Gets or sets Delivery Method.
    /// </summary> 
    public virtual string fDeliveryMethod { get; set; }

    /// <summary>
    /// Gets or sets Invoice Number.
    /// </summary> 
    public virtual int? fARInvoiceNumber { get; set; }



    public virtual tARCustomer Customer { get; set; }

    public virtual IList<tARPaymentInvoice> PaymentInvoices { get; set; }        

    #endregion

    #region Methods
    /// <summary>
    /// retrieve Hash Code.
    /// </summary>
    /// <returns>The method get code.</returns>
    public override int GetHashCode()
    {
        return ID.GetHashCode();
    }
    #endregion
}

public partial class tARPaymentInvoice 
{
    #region Constructor
    /// <summary>
    /// Initializes a new instance of the <see cref="tARPaymentInvoice"/> class.
    /// </summary>
    public tARPaymentInvoice()
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="tARPaymentInvoice"/> class.
    /// </summary>
    /// <param name="fPaymentInvoiceID">The Invoice ID.</param>   
    public tARPaymentInvoice(System.Guid fPaymentInvoiceID)
    {
        this.ID = fPaymentInvoiceID;
    }
    #endregion

    #region Properties
    /// <summary>
    /// Gets or sets fPaymentInvoiceID.
    /// </summary>
    public virtual System.Guid fPaymentInvoiceID { get; set; }

    /// <summary>
    /// Gets or sets fPaymentID.
    /// </summary>
    public virtual System.Guid fPaymentID { get; set; }

    /// <summary>
    /// Gets or sets fInvoiceID.
    /// </summary>
    public virtual System.Guid fInvoiceID { get; set; }           


    /// <summary>
    /// Gets or sets tARPayment.
    /// </summary>
    public virtual tARPayment Payment { get; set; }

    /// <summary>
    /// Gets or sets tARInvoice.
    /// </summary>
    public virtual tARInvoice Invoice { get; set; }

    #endregion

    #region Methods
    /// <summary>
    /// get hash codes.
    /// </summary>        
    /// <returns>The hash code.</returns>
    public override int GetHashCode()
    {
        return ID.GetHashCode();
    }
    #endregion
}

CREATE VIEW vCustomerAmount AS
SELECT fCustomerID,
       ISNULL(
                (SELECT SUM(payinv.fAmount) AS Expr1
                 FROM dbo.tARPayment AS pay
                 INNER JOIN dbo.tARPaymentInvoice AS payinv ON pay.fPaymentID = payinv.fPaymentID
                 INNER JOIN dbo.tARInvoice AS inv ON payinv.fInvoiceID = inv.fARInvoiceID
                 WHERE (pay.fIsPosted = CASE pay.fPaymentType WHEN 'CM' THEN 0 WHEN 'EPD' THEN 0 ELSE 1 END)
                   AND (inv.fCustomerID <> dbo.tARCustomer.fCustomerID)
                   AND (pay.fCustomerID = dbo.tARCustomer.fCustomerID)), 0) [Amount]
FROM dbo.tARCustomer
GROUP BY fCustomerID

public class CustomerAmount
{
    public int fCustomerID { get; set; }
    public decimal Amount { get; set; }
}

List<CustomerAmount> customerAmounts = session.Query<CustomerAmount>().ToList();

SELECT T.fCustomerID,
       coalesce( SUM( payinv.fAmount ), 0 ) as SumAmt
   FROM 
      dbo.tARCustomer T
         JOIN dbo.tARPayment AS pay
            ON T.fCustomerID = pay.fCustomerID 
            AND pay.fIsPosted = CASE pay.fPaymentType 
                                WHEN 'CM' THEN 0 
                                WHEN 'EPD' THEN 0 
                                ELSE 1 END
             JOIN dbo.tARPaymentInvoice AS payinv 
               ON pay.fPaymentID = payinv.fPaymentID
               INNER JOIN dbo.tARInvoice AS inv 
                  ON payinv.fInvoiceID = inv.fARInvoiceID
                 AND inv.fCustomerID <> T.fCustomerID
   GROUP BY 
      T.fCustomerID