选择与oledb

Question

我不能选择..。我不能在一个日期内做一个选择，比如uma，variavel，que，行列式，一个量化的网格，一个计算的MesesDemanda，一个日期之前和之后的一个。

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;
            }

Answer 1

使用下面这样的参数

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

现在可以设置如下所示的值

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

如果您需要接受qtdHistSaida列的和，则可以如下所示更改sql语句

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

现在可以使用ExecuteScalar方法获得和值，如下所示

var result  = cmd.ExecuteScalar();