这个索引怎么看啊

Question

我的表名是正确的 默认值是0  可是它怎么老是这个错误啊 

Answer 1

SQL语句对吗?给个DEMO你自己看看.
public static void ReadData(string connectionString)
{
    string queryString = "SELECT DISTINCT CustomerID FROM Orders";
    using (OleDbConnection connection = new OleDbConnection(connectionString))
    {
        OleDbCommand command = new OleDbCommand(queryString, connection);        connection.Open();
        OleDbDataReader reader = command.ExecuteReader();        int customerID = reader.GetOrdinal("CustomerID");        while (reader.Read())
        {
            Console.WriteLine("CustomerID={0}", reader.GetString(customerID));
        }
        reader.Close();
    }
}

Answer 2

把reader.GetOrdinal那个提出来放到变量里

Answer 3

reader.GetOrdinal("CustomerID")得到的是CustomerID，相当于行号，你用Reader.GetInt32(ID)相当于访问ID这一列，当然不对。