SQL Server STRING_AGG() : equivalent in Linq

Question

This is my table tbl_emp:

This is the result I need:

In SQL Server 2017, I can use STRING_AGG to get the desired result:

SELECT 
    name, 
    STRING_AGG(email,'') 'email', STRING_AGG(email2,'') 'email2'
FROM
    tbl_emp
GROUP BY 
    name

How can I get the same result in Linq? Any help would be greatly appreciated.

Answer 1

In question not given any information about which ORM you are using, so i try to show one example to this case in linq to objects in c#, not fully solution for question

String_Agg aggregation function takes a set of values and combines them into a string, using a supplied separator. In LINQ (linq to objects) you may do it by using Group By, i think this example helps you:

class Program
    {
        static void Main(string[] args)
        {
            var emails = new List<EmailData>() { 
                new EmailData() {Name="Sam", Email="Email1" },
                new EmailData() {Name="Sam", Email="Email2" },
                new EmailData() {Name="Ted", Email="Email3" },
                new EmailData() {Name="Sam", Email="Email4" },
                new EmailData() {Name="Sam", Email="Email5" }
            };
            var grouping = emails.GroupBy(x => x.Name);
            foreach (var group in grouping)
            {
                Console.WriteLine(
                    $"{group.Key}: {string.Join(", ", group.Select(x => x.Email))}");
            }
            Console.ReadKey();
        }
    }
    public class EmailData
    {
        public string Name { get; set; }
        public string Email { get; set; }
    }

Result: