将 SQL 查询更改为 LINQ，asp.net MVC

Question

如何将此 SQL 查询更改为 LINQ？试了好几次都没有用

SELECT Payment.ID, Payment.TotalGroupID, PaymentTrans.PaymentID, PaymentTrans.TotalGroupID as TotalGroupID1, PaymentTrans.TransferStatus
FROM PaymentTrans INNER JOIN Payment
ON (PaymentTrans.PaymentID = Payment.ID OR PaymentTrans.TotalGroupID = payment.TotalGroupID)
WHERE (PaymentTrans.TransferStatusis NULL  OR (PaymentTrans.TransferStatus <> '01' and PaymentTrans.TransferStatus <> '02'))

这是我的尝试

var a= (from x in db.PaymentTransactions
        join p in db.Payments
        on
        x.PaymentID equals p.ID
        where x.TransferStatus== null || (x.TransferStatus!= "01" && x.TransferStatus!= "02")
                            select new { x, p }).ToList();

但它仍然是 LINQ 错误，因为在我的查询中，我在 ON 子句中有 2 个条件。谢谢

Answer 1

您不能在 LINQ 中添加多个 ON。你上面问题的解决方法可以这样解决。

提示: 只需使用多个 Where.

var result = 
(
    from trans in db.PaymentTransactions
    join payment in db.payments
    on trans.PaymentID equals payment.ID
    where trans.TotalGroupID == payment.TotalGroupID
    where x.TransferStatus== null || (x.TransferStatus!= "01" && x.TransferStatus!= "02")
    select new 
    {
        //your properties
    }

).ToList();

Answer 2

试试这个

var query = (from x in db.PaymentTransactions
             join p in db.Payments 
             on x.PaymentID equals p.ID //main condition of join
             where  ((x.TransferStatus == null || 
             (x.TransferStatus != "01" && x.TransferStatus!= "02")) //your `where` condition
             || x.TotalGroupID == p.TotalGroupID) //your second or join
             select new {x,p})
            .ToList();

Answer 3

上面的答案都过滤了两个条件，他们应该根据问题（PaymentID 或 TotalPaymentID）过滤其中一个条件。您可以编写两个单独的查询并使用联合或在过滤前使用笛卡尔积。

var result = (from paymentTransaction in db.PaymentTransactions
                      join payment in db.Payments on paymentTransaction.PaymentID equals payment.ID
                      where paymentTransaction.TransferStatus == null || (paymentTransaction.TransferStatus != "01" && paymentTransaction.TransferStatus != "02")
                      select new { paymentTransaction, payment }).Union
                     (from paymentTransaction in db.PaymentTransactions
                      join payment in db.Payments on paymentTransaction.TotalGroupID equals payment.TotalGroupID
                      where paymentTransaction.TransferStatus == null || (paymentTransaction.TransferStatus != "01" && paymentTransaction.TransferStatus != "02")
                      select new { paymentTransaction, payment });

        var cartResult = from paymentTransaction in db.PaymentTransactions
                         from payment in db.Payments
                         where paymentTransaction.PaymentID == payment.ID || paymentTransaction.TotalGroupID == payment.TotalGroupID
                         where paymentTransaction.TransferStatus == null || (paymentTransaction.TransferStatus != "01" && paymentTransaction.TransferStatus != "02")
                         select new { paymentTransaction, payment };

将 SQL 查询更改为 LINQ，asp.net MVC

Change SQL Query to LINQ, asp.net MVC

c#

linq

sql-server

sql-to-linq-conversion