C# 使用oledb进行选择

我不能做选择。。。 我不能在围棋中选择日期 计算所需数量的变化率 计算了一个日期之前和一个日期之后

for (int i = 1; i <= MesesDemanda; i++)
            {
                int cont = 0;
                DateTime dataposterior = DateTime.Now, dataanterior = DateTime.Now;
                dataanterior = dataanterior.AddMonths(i);
                dataposterior = dataposterior.AddMonths(-(i - 1));
                con.Open();
                cmd = new OleDbCommand("SELECT HistSaida.dataHistSaida, HistSaida.idProdutoHistSaida, HistSaida.qtdHistSaida FROM HistSaida WHERE (((HistSaida.dataHistSaida) BETWEEN #" + dataanterior + "# AND #" + dataposterior + "#) AND idProdutoHistSaida = " + idProduto + ")", con);
                dr = cmd.ExecuteReader();
                if (dr.HasRows)
                {
                    while (dr.Read())
                    {
                        Demanda = Demanda + Convert.ToInt32(dr["qtdHistSaida"]);
                        cont = 1;
                    }
                }
                dr.Close();
                con.Close();
                Valordivisao = Valordivisao + cont;
            }

---

for（int i=1；i使用如下参数

cmd = new OleDbCommand("SELECT dataHistSaida, idProdutoHistSaida, qtdHistSaida FROM HistSaida WHERE ((dataHistSaida <=?  AND dataHistSaida >= ?) AND idProdutoHistSaida = ?)", con);

cmd.Parameters.AddWithValue("@p1", dataanterior );
cmd.Parameters.AddWithValue("@p2", dataposterior );
cmd.Parameters.AddWithValue("@p3", idProduto );

如果需要求
qtdhitsaida
列的和，则可以按如下所示更改sql语句

SELECT SUM(qtdHistSaida) FROM HistSaida WHERE ((dataHistSaida <=?  AND dataHistSaida >= ?) AND idProdutoHistSaida = ?)

var result  = cmd.ExecuteScalar();

条件表达式中的数据类型不匹配且变量更多？我需要更多帮助，我无法在数据库中进行选择您为dataHistSaida和idProdutoHistSaida列提供的数据类型是什么？TahHistSaida是日期，idProdutoHistSaida是整数