Question

我的SQL查询按预期工作：

SELECT SUM(outcome), toaddress
FROM lot l
JOIN incomingpayment ip
ON l.incomingpayment_id = ip.id
WHERE outcome > 0
GROUP BY ip.toaddress
ORDER BY SUM(outcome) DESC

我试图把它变成LINQ语句，但无论如何都没有取得很大的成功：

var result = 

from l in session.Query<Lot>().ToList()
join ip in session.Query<IncomingPayment>().ToList()
on l.IncomingPayment equals ip
where l.Outcome > 0
group ip by new {ip.ToAddress}
into g
select new
{
   Address = g.Key,
   SumAmount = g.Sum(x => x.Outcome)
};

最后一行中的

Outcome是Lot字段，因为我正在对IncomingPayment（group ip...）进行分组。 g.Sum()来电时无法使用。

我在这里缺少什么？

Answer 1

你可以试试这个：

var result = from g in (from l in session.Query<Lot>().ToList()
             join ip in session.Query<IncomingPayment>().ToList()
             on l.IncomingPayment equals ip.Id
             where l.Outcome > 0
             select new { Address = ip.ToToAddress, Outcome = l.Outcome})
             group g by g.Address
             select new
             {
                 Address = g.Key,
                 SumAmount = g.Sum(x => x.Outcome)
             };

或更明确地说：

Lots = session.Query<Lot>().ToList();
IncomingPayments = session.Query<IncomingPayment>().ToList();

var result = Lots.Join(IncomingPayments, 
                       x=>x.IncomingPayment,  
                       y=>y.Id,
                       (x,y) => new
                       {
                           Address = x.ToToAddress,
                           OutCome = y.Outcome
                       }).GroupBy(x => x.Address, 
                                  x => x.Outcome,
                                  (kew, group) =>
                                  {
                                      Address = key,
                                      SumAmount = group.Sum()
                                  });

无法将mysql查询转换为linq语句

1 个答案: