Question

I have a LINQ query which returns a set of rows. The structure is:

NAME,    col1, col2, col3, col4
name1     1    null  null  null
name1    null   1    null  null
name1    null  null   1     1 

As a result I want to have one row containing

name1     1     1     1     1

So I want to group those results by name and merge (sum?) the other columns so if I have not null in one of the rows in a column – I will receive anything except null.

Thanks for help!

Answer 1

class MyObj
{
    public string Name { get; set; }
    public int? Col1 { get; set; }
    public int? Col2 { get; set; }
    public int? Col3 { get; set; }
    public int? Col4 { get; set; }
}

List<MyObj> l = new List<MyObj> {
    new MyObj {Name = "name1", Col1 = 1 },
    new MyObj {Name = "name1", Col2 = 1 },
    new MyObj {Name = "name1", Col3 = 1 },
    new MyObj {Name = "name1", Col4 = 1 }
};

var qry = from o in l
          group o by o.Name into g
          select new
          {
              Name = g.Key,
              Col1 = g.Any(e => e.Col1.HasValue) ? (int?)1 : null,
              Col2 = g.Any(e => e.Col2.HasValue) ? (int?)1 : null,
              Col3 = g.Any(e => e.Col3.HasValue) ? (int?)1 : null,
              Col4 = g.Any(e => e.Col4.HasValue) ? (int?)1 : null
          };