SQL Server and C#: get last inserted id

Question

public static void CreateSocialGroup(string FBUID)
{
    string query = \"INSERT INTO SocialGroup (created_by_fbuid) VALUES (@FBUID); SELECT @@IDENTITY AS LastID\";
         


        

Answer 1

SqlCommand command = new SqlCommand("select max(id) from SocialGroup ", connection);
int lastId = (int)command.ExecuteScalar();

Answer 2

Personally, I would re-write your code to use Parameters. You could either use an InputOutput parameter or an Output Parameter. However, using a Return Value in your SQL would also work.

Full examples on this can be found on MSDN.

I would also use Scope_Identity() rather than @@Identity this will ensure that you will reveice the ID that relates to the current transaction. Details on Scope_Identity can be found here.

Answer 3

If your server supports the OUTPUT clause you could try it with this one:

public static void CreateSocialGroup(string FBUID)
{
    string query = "INSERT INTO SocialGroup (created_by_fbuid) OUTPUT INSERTED.IDENTITYCOL VALUES (@FBUID)";

    using (SqlConnection connection = new SqlConnection(ConnectionString))
    {
        SqlCommand command = new SqlCommand(query, connection);
        command.Parameters.AddWithValue("@FBUID", FBUID);

        connection.Open();
        var _id = command.ExecuteScalar();
    }
}