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使用SUM和GROUP BY的带子选择查询的LINQ?

sum subquery group-by linq

Martin · 技术社区 · 15 年前

有人能帮我查询一下LINQ吗?我已经转换了其中的大部分,但在存储过程中有一个子查询,我无法确定如何进行转换。

基本上这是旧的存储过程(为了方便而截断)

 SELECT  M.Period AS 'Period' ,
            C.Code AS 'Group' ,
            C.ClientCode AS 'Code' ,
            C.ClientName AS 'Name' ,
            ( SELECT    SUM(Amount) AS Expr1
              FROM      M
              WHERE     ( ClientCode = C.ClientCode )
              GROUP BY  ClientCode
            ) AS 'Amount' ,

从上面可以看到,子查询是这样的

              SELECT    SUM(Amount) AS Expr1
              FROM      M
              WHERE     ( ClientCode = C.ClientCode )
              GROUP BY  ClientCode
            ) AS 'Amount'

所以我已经完成了所有的连接,到目前为止我已经完成了,并且它工作了。

 var test = from c in C join h in H on c.Code 
            equals h.Code join m in M on c.ClientCode   
            equals m.ClientCode 
            select new 
            { 
                Period=m.Period,
                Group=c.Code,
                Code= c.ClientCode,
                Name= c.ClientName,
                <-- Here is where i need the sub select query above -->
            };

但是我对如何进行子查询感到茫然。列的名称将是您在旧存储过程中能够看到的金额。

如果有任何反馈或帮助,我将不胜感激

谢谢

1 回复 | 直到 15 年前

Raymund 15 年前

我不确定SQL查询的最后一部分,但我假设是这样的

SELECT  M.Period AS 'Period' ,
C.Code AS 'Group' ,
C.ClientCode AS 'Code' ,
C.ClientName AS 'Name' ,
( SELECT    SUM(Amount) AS Expr1
  FROM      M
  WHERE     ( ClientCode = C.ClientCode )
  GROUP BY  ClientCode
) AS 'Amount' 
from C inner join M on C.ClientCode = M.ClientCode

所以你的LINQ就是这个

var test = from c in db.C
select new {
  Period = c.M.Period,
  Group = c.Code,
  Code = c.ClientCode,
  Name = c.ClientName,
  Amount = (System.Int32)
    ((from m0 in db.M
    where
      m0.ClientCode == c.ClientCode
    group m0 by new {
      m0.ClientCode
    } into g
    select new {
      Expr1 = (System.Int32)g.Sum(p => p.Amount)
    }).First().Expr1)
}

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