Group by in LINQ C#

In LINQ, Group By method is used to group of source element by using single or more than one property of element.

Here is an example of Group by:

In below LINQ Query, the order records is grouped by customer ID and returns total count of order for each customer.

    var result = _dbContext.Orders.GroupBy(x => x.CustomerID)

                .Select(y => new

                {

                    CustomerID = y.Key,

                    Count = y.Count()

                }).ToList();

Group by on multiple Columns:

In below LINQ Query, the order records is grouped by State and City (more than one columns) and it returns the count of order for each City.

     var result = _dbContext.Orders.GroupBy(x => new { x.State, x.City } )

                .Select(y => new

                {

                    State= y.Key.State,

                    City = y.Key.City,

                    Count = y.Count()

                }).ToList();