Question

所以这就是......

我有两张桌子

表1：购买

id | aid | amount
1     1      5
2     3      8
3     7      2
4     1      3

表2：给定

id | aid | amount
1     2      4
2     1      3
3     7      5
4     1      1

我想要做的是通过援助字段将两个表和组的数量相加，但是在不同的行中。所以这两个表的结果将是：

结果

aid | sum1 | sum2
 1     8      4
 2     0      4
 3     8      0
 7     2      5

LINQ在VB.net中... 到目前为止我所拥有的是：

Dim one = From r In Purchase 
             Select r.aid, r.amount
             Group By aid
             Into total1 = Sum(amount)

Dim two = From p In Given
            Select p.aid, p.amount
            Group By aid
            Into total2 = Sum(amount)

Dim final = From p In one
            Join r In two On p.aid Equals r.aid


[ POPULATE LIST VIEW ]

For Each itm In final
   Dim X As ListViewItem
   X = lstPregledSaldo.Items.Add(itm.p.aid)
   X.SubItems.Add(itm.p.total1)
   X.SubItems.Add(itm.r.total2)
 Next

但是这会产生我的左连接，如果有帮助的元素不在表格中，它不会在查询中使用它...我不知道如何解决这个问题：S

Answer 1

虽然这不是您正在寻找的答案，但您可以使用Linqer或LINQpad将此SQL转换为LINQ。

WITH T AS (
    SELECT P.aid
          ,SUM(P.amount) As 'tp'
          ,0             As 'tg'
    FROM purchase P
    GROUP BY P.aid
  UNION
    SELECT G.aid
          ,0
          ,SUM(G.amount) 
    FROM given g
    GROUP BY g.aid
)
SELECT aid
      ,SUM(tp) AS 'Total Purchase'
      ,SUM(tg) As 'Total Given'
FROM T
GROUP BY aid

我还在SQL Fiddle上创建了一个测试环境。

Answer 2

Dim Purchases = (From r In db.Purchase
               Select r.aid, r.amount).ToList()

Dim Given = (From p In db.Given
            Select p.aid, p.amount).ToList()


Dim aidValues = Purchases.Concat(Given).Select(Function(x) x.aid).OrderBy(Function(x) x).Distinct()

For Each a In aidValues
    Dim sumP = Purchases.Where(Function(x) x.aid = a).Sum(Function(y) y.amount)
    Dim sumG = Given.Where(Function(x) x.aid = a).Sum(Function(y) y.amount)

    Console.WriteLine("aid {0}, sum1 {1}, sum2 {2}", a, sumP, sumG)
Next

您可以使用concat从两个表格中选择所需的值（在这种情况下，列出不同的援助记录）。然后计算循环中每个表的总数。

结果：

aid 1, sum1 8, sum2 4
aid 2, sum1 0, sum2 4
aid 3, sum1 8, sum2 0
aid 7, sum1 2, sum2 5

Sum和Group多个Linq列表

2 个答案: