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LINQ 2 SQL分组问题

group-by linq-to-sql

Jack Marchetti · 技术社区 · 16 年前

var groups = from p in dc.Pool
             join pm in dc.PoolMembers on p.ID equals pm.PoolID
             group p by p.Group into grp
             select new { grp.ID };

这不管用。基本上我想进行分组,然后选择某些列,但是当我这样做时 select new { grp. } 我没有理智,所以我明显做错了什么。

有什么想法吗?

3 回复 | 直到 16 年前

Gregoire 16 年前

我不确定,但是,下面的代码有效吗?

var groups = from p in dc.Pool
             join pm in dc.PoolMembers on p.ID equals pm.PoolID
             group p by p.Group into grp
             select grp.Select(g=> g.ID);

编辑

var groups = from p in dc.Pool
             join pm in dc.PoolMembers on p.ID equals pm.PoolID
             group p by p.Group into grp
             select grp.Select(g=> new{ 
                  Id = g.Id, 
                  GroupName = grp.Key.Name,
                  Contribution = pm.Contribution,
                  GameName = p.GameName, });

alejandrobog 16 年前

我想这就是你要找的

      var groups = from p in dc.Pool
               join pm in dc.PoolMembers on p.ID equals pm.PoolID
               group p by p.Group into grp
               select new { grp.Key.ID, GroupName = grp.Key.Group.Name, grp.Key.GameName };

Amy B 16 年前

var pools = 
  from p in dc.Pool
  select new
  {
    p.ID,
    GroupName = p.Group.Name,
    Contribution = p.PoolMembers.Sum(pm => pm.Contribution),
    p.GameName
  };

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