dapper 跨表查询

    public class U
    {
        public long user_id;
        public string user_name;
    }

    public class B
    {
        public string brand_name;
        public long creator;
        public U user;
    }

            List<B> blist = null;
            using (var db = new SqlConnection(sqlconnStr))
            {
                blist = db.Query<B, U, B>(
                    @"select * from Brand b left join [User] u on u.user_id = b.creator", (b, u) => { 
                        b.user = u; return b; }, splitOn: "user_id").ToList();
            }

            foreach (var item in blist) { 
                Console.WriteLine($"{item.creator} {item.brand_name} {item.user.user_name}");
            }