使用linq2db实现不同类型的联合

using LinqToDB;
using LinqToDB.Data;
using LinqToDB.Mapping;
using System;
using System.Collections.Generic;
using System.Linq;

// 定义实体类
[Table(Name = "Table1")]
public class Table1Entity
{
    [Column(Name = "Id"), PrimaryKey, Identity]
    public int Id { get; set; }

    [Column(Name = "Name")]
    public string Name { get; set; }
}

[Table(Name = "Table2")]
public class Table2Entity
{
    [Column(Name = "Id"), PrimaryKey, Identity]
    public int Id { get; set; }

    [Column(Name = "Description")]
    public string Description { get; set; }
}

// 创建数据上下文
public class MyDataContext : DataConnection
{
    public MyDataContext() : base("MyConnectionString")
    {
    }

    public ITable<Table1Entity> Table1 => GetTable<Table1Entity>();
    public ITable<Table2Entity> Table2 => GetTable<Table2Entity>();
}

// 执行联合查询
public class Program
{
    public static void Main()
    {
        using (var db = new MyDataContext())
        {
            var query = db.Table1.Select(t => new { t.Id, t.Name })
                .Union(db.Table2.Select(t => new { Id = t.Id + 100, Name = t.Description }));

            var result = query.ToList();

            foreach (var item in result)
            {
                Console.WriteLine($"Id: {item.Id}, Name: {item.Name}");
            }
        }
    }
}