Question

我再次挣扎，所以任何帮助都会感激不尽。

我有以下LINQ可以回读一个数据列表：

public static List<tblWeight> GetWeights(string memberid, string locationid, string buyer, string subcategory, string product)
        {

            MyEntity getweights = new MyEntity ();

            var r = (from p in getweights.tblWeights
                     where p.MemberId == memberid &&
                              p.LocationId == locationid
                     select p);

            if (buyer != "Not Specified")
                r = r.Where(p => p.UnitUserField1 == buyer);

            if (subcategory != "Not Specified")
                r = r.Where(p => p.UnitUserField2 == subcategory);

            if (product != "Not Specified")
                r = r.Where(p => p.IDDesc == product);

            return r.ToList();
        }

可爱！

我现在要做的是根据这个结果集和单位ID（IDDesc），然后转到tblPurchase，从tblPurchases中拉回几列并对列进行分组。

例如，我们看起来像tblWeight：

MemberID    LocationID  Buyer   SubCategory IDDesc
1            1           Cat1   Sub1        ab
1            1           Cat1   Sub1        abc
1            1           Cat1   Sub2        abcd

用户在子类别中搜索Sub1，上面的LINQ完成了这一操作并从上面拉回前两行。细

我现在需要LINQ去做tblPurchases：

MemberID    LocationID  IDDesc  SupplierID  SupplierStatus
1           1          ab        Sup1            Live
1           1          abc       Sup1            Live
1           1          abcd      Sup2            Dead

然后撤回以下结果，以便它在MemberID，LocationID和IDDesc上加入，但只选择tblPurchases。

Sup1 Live（或tblPurchases中的所有列，只是分组/不同）

我试图添加一个连接，但无论有多少不同的变化，我仍然遇到了红色的厄运！[/ p>

如果有人可以提供帮助，可以再次提供啤酒/吻。

Answer 1

以下LINQ查询应该执行您想要的操作：

var result = from w in tblWeight
             where w.SubCategory == "Sub1"
             join p in tblPurchases on
                new { w.MemberID, w.LocationID, w.IDDesc } equals
                new { p.MemberID, p.LocationID, p.IDDesc }
             group p by new { p.SupplierID, p.SupplierStatus } into pg
             select pg.Key;

变量result是一个包含SupplierID和SupplierStatus元组的列表。

如果你还想把条件部分放在那里，它会变得有点复杂。这是如何做到的：

var weights = from w in tblWeight
              select w;
weights = weights.Where(w => w.SubCategory == "Sub1");
// You can add additional where clauses here.

// Now join with tblPurchases and group by SupplierID and SupplierStatus.
var result =
    weights.Join(tblPurchases,
                 w => new { w.MemberID, w.LocationID, w.IDDesc },
                 p => new { p.MemberID, p.LocationID, p.IDDesc },
                 (w, p) => p)
           .GroupBy(p => new { p.SupplierID, p.SupplierStatus },
                    (k, ps) => new
                                {
                                    k.SupplierID,
                                    k.SupplierStatus,
                                    TotalQty = ps.Sum(p => p.PurchaseQty)
                                });

LINQ加入多个Where子句

1 个答案: