C#中的SQL查询错误

Question

我是SQL Queries的新手,我想从SettlementTypeSetup(表)加载"PSX LAGA"值,其中结算类型等于Regular/BO,Sale/Purchase等于"Purchase";

下面是我的代码,这是我的表

private void Load_Settlement_Type()
        {
        SqlCeConnection conn = null;
        SqlCeCommand cmd = null;
        SqlCeDataReader rdr = null;

        try
        {
            conn =
                new SqlCeConnection(
                   @"Data Source=|DataDirectory|\Database.sdf;Persist Security Info=False");
            conn.Open();
            cmd = new SqlCeCommand("SELECT PSXLaga FROM SettlementTypeSetup where SettlementType=BO/REGULAR;" , conn);
            rdr = cmd.ExecuteReader();

            if (rdr == null)
            {
                MessageBox.Show("Reader is null");
            }
            else
            {
                while (rdr.Read())
                {
                    PSXLAGATEXT  = rdr["PSXLaga"].ToString();

                }

                 rdr.Close();
                cmd.Dispose();

            }
        }
        finally
        {
            conn.Close();
            PSXLagaTextBox.Text = PSXLAGATEXT;

        }

    }

****它给出了错误:列名:BO/REGULAR未找到,而BO/REGULAR不是列名,BO/REGULAR是SettlementType(Column)的值,条件应如下所示.**

给我PSX Laga Value,其中SettlementType(Column)值为BO/REGULAR,Sale/Purchase(Column)为Purchase.

**

Answer 1

您需要写入您的值,''因为它是一个字符串.其他方法是使用参数.

cmd = new SqlCeCommand("SELECT PSXLaga FROM SettlementTypeSetup where SettlementType=@Type" , conn);

cmd.Parameters.AddWithValue("@Type", "BO/REGULAR");