Question

我有这个简单的sql，完全符合我的需要......

SELECT MIN(pb.Id) AS Id, MIN(pb.Quantity) AS Requested, SUM(pbi.Quantity) AS Total
FROM PickBatchItems AS pb
LEFT JOIN PickBatchItemLocations AS pbi ON pb.Id = pbi.PickBatchItemId
GROUP BY pb.Id

结果......

Id, Requested, Total
 1    100       NULL
 2    200       165
 3    200       NULL

这正是我想要的，但我需要这个在Linq。

到目前为止，我有......

var pick = (from pb in db.PickItems
           join pbi in db.PickItemLocations on pb.Id equals pbi.PickBatchItemId into TempJoin
           from resList in TempJoin.DefaultIfEmpty()
           where pb.Id == iPickItemId
           group resList by pb.Id into g
           select new
           {
               Id = g.Key,
               RequestedQuantity = g.Min(???????????????????????),
               SentQuantity = g.Sum(a => a.Quantity == null ? 0 : a.Quantity),
           }).FirstOrDefault();

如何获得 RequestedQuantity ？

更新

感谢'大卫B'我有答案：

var pick = (from pb in db.PickBatchItems
            join pbi in db.PickBatchItemLocations on pb.Id equals pbi.PickBatchItemId into TempJoin
            from resList in TempJoin.DefaultIfEmpty()
            where pb.Id == iPickItemId
            group new { PickItem = pb, PickItemLocation = resList } by pb.Id into g
            select new
            {
                Id = g.Key,
                RequestedQuantity = g.Min(a => a.PickItem.Quantity),
                SentQuantity = g.Sum(a => a.PickItemLocation.Quantity == null ? 0 : a.PickItemLocation.Quantity),
            }).FirstOrDefault();

即使PickBatchItemLocations表为空，这也会加入并返回我的两个表。

Answer 1

假设PickItems.Id是主键，似乎加入是不需要旅行的道路的第一步。

from pb in db.PickItems
where pb.Id = iPickItemId //this wasn't in the original sql
select new
{
  Id = pb.Id,
  RequestedQuantity = pb.Quantity,
  SentQuantity = pb.PickItemLocations.Sum(pbi => pbi.Quantity)
};

如果您仍想走很长的路，请执行以下操作：

group new {PickItem = pb, PickItemLocation = resList } by pb.Id into g
select new
{
  Id = g.Key,
  RequestedQuantity = g.Min(x => x.PickItem.Quantity),
  SentQuantity = g.Sum(x => x.PickItemLocation.Quantity ?? 0)
}

Sql转换为Linq - Left Join，Group，Min和Sum

1 个答案: