PetaPoco中使用Where in

petapoco中使用in关键字需要使用命名参数，否则是无效的(或者只查出第一个条件的记录)

例如：

  public List<model> GetRate(string from)
        {
            using (var db = MDb())
            {
                var sql = new StringBuilder();
                sql.Append(@"SELECT * FROM TABLE WHERE 1=1 AND effectivetime<=@effectivetime ");

                var para = new ArrayList
                {
                    new { effectivetime = DateTime.Now }
                };

                #region 处理查询条件
                if (!string.IsNullOrEmpty(from))
                {
                    if (from.IndexOf(",", StringComparison.Ordinal) > 0)
                    {
                        var fromTags = from.Split(',');
                        para.Add(new { from = fromTags });
                        sql.Append(" AND from.Name IN (@from)");
                    }
                    else
                    {
                        para.Add(new { from });
                        sql.Append(" AND from.Name =@from");
                    }
                }              #endregion

                return db.Fetch<model>(sql.ToString(), para.ToArray());
            }
        }