分批拼接SQL IN 查询需要的ID字段值，解决IN 查询的ID过多问题

SQL查询使用的IN条件字段很多的时候，会造成SQL语句很长，大概SQL语句不能超过8K个字符，也有说IN不能超过1000个条件，总之太长了不行，需要拆分条件分批处理。下面提供一个将Int类型的条件字段值进行字符串拼接的方法。看代码：

class Program
    {
        static void Main(string[] args)
        {
            int[] source = { 1,2,3,4,5,6,7,8,9,10};
            ShowSource(source);

            List<string> list = BatchJoinArray2String(source, 5).ToList();
            ShowList(list);

            List<string> list2 = BatchJoinArray2String(source, 3).ToList();
            ShowList(list2);

            Console.Read();
        }

        static void ShowSource(int[] source)
        {
            string sourceStr = string.Join(",", source);
            Console.WriteLine("Source Arrar:{0}", sourceStr);
        }

        static void ShowList(List<string> lst)
        {
            foreach (string item in lst)
                Console.WriteLine("\""+item+"\"");
            Console.WriteLine("--------------------");
        }

        static IEnumerable<string> BatchJoinArray2String(int[] arrSource,int batchSize)
        {
            if (batchSize <= 1) throw new ArgumentOutOfRangeException("batchSize 批处理大小不能小于1");
           
            if (arrSource.Length > batchSize)
            {
                int[] arr10 = new int[batchSize];
                int j = 0;
                for (int i = 0; i < arrSource.Length; i++)
                {
                    if (j < batchSize)
                    {
                        arr10[j++] = arrSource[i];
                    }
                    else
                    {
                        j = 0;
                        string str = string.Join(",", arr10);
                        arr10[j++] = arrSource[i];
                        yield return str;

                    }
                }
                if (j > 0) //还有剩余
                {
                    int[] arr0 = new int[j];
                    Array.Copy(arr10, arr0, j);
                    string str = string.Join(",", arr0);
                    yield return str;
                }
            }
            else
            {
                string str = string.Join(",", arrSource);
                yield return str;
            }
        }
    }

运行这个示例程序，得到下面输出：

Source Arrar:1,2,3,4,5,6,7,8,9,10
"1,2,3,4,5"
"6,7,8,9,10"
--------------------
"1,2,3"
"4,5,6"
"7,8,9"
"10"
--------------------

在你的程序中，可以像下面这样使用：

 string sql_update=@"
update t2 set 
  AA  =1 ,
  BB ='2222'
FROM [MyTable] as t2 
WHERE t2.[ID] in  ( @IDs );
";
//每次更新50条记录
            using (SqlConnection conn = new SqlConnection(DefaultConnectionString))
            {
                conn.Open();
                foreach (string ids in BatchJoinArray2String(XXXIds.ToArray(), 50))
                {
                    string sql = sql_update.Replace("@IDs", ids);
                    SqlHelper.ExecuteNonQuery(conn, CommandType.Text, sql);
                }
              
                conn.Close();
            }