C# linq group by multiple columns

This post show you how to use linq group by multiple columns in c#.

var result = 
    from o in db
    group o by (o.Column1, o.Column2) into g
    select new (g.Key.Column1, g.Key.Column2, Total: g.Sum(o => o.Quantity));

or you can write linq group by multiple columns to list in c# as shown below.

var result = 
    from o in db
    group o by (o.Column1, o.Column2) into g
    select new {
                   Column1 = g.Key.Column1,
                   Column2 = g.Key.Column2,
                   Total = g.Sum(o => o.Quantity)
               }

if you want to write c# linq group by multiple columns count, you can modify as shown below.

var result = 
    from o in db
    group o by (o.Column1, o.Column2) into g
    select new {
                   Column1 = g.Key.Column1,
                   Column2 = g.Key.Column2,
                   Total = g.Count()
               }

or you can use method

var result = db.GroupBy(x => (x.Column1, x.Column2))
    .Select(g => (g.Key.Column1, g.Key.Column2, Total: g.Sum(x => x.Quantity)));