如何从C＃获取MS Access数据库中的列数

Question

I am trying to get a sum with a column from a ms access database but so not nothing has worked this is what I have

      Conn.Open();
            Command.CommandText = "Select SUM(c_qty) from COLLVAULT_COINS WHERE c_type!='US Currency' AND c_type!='World Currency' AND c_type!='World Coins' AND c_listName = '" + activeCollection + "'";
            int total_1 = Convert.ToInt32(Command.ExecuteScalar());
            //total sum - get how many match the query
            lblcollectedcount.Text = Convert.ToString(total_1);
            Conn.Close();

any help would be nice.

Answer 1

You could try something like this, assuming you want the number of records that were matched with your query:

Conn.Open();
Command.CommandText = "Select SUM(c_qty) as sum, Count(*) as count from COLLVAULT_COINS WHERE c_type <> 'US Currency' AND c_type <> 'World Currency' AND c_type <> 'World Coins' AND c_listName = '" + activeCollection + "'";    //

int total_matches = 0;

using (MySqlDataReader dataReader = Command.ExecuteReader())
{
    if (dataReader.Read()) 
    {
        lblcollectedcount.Text = Convert.ToString(dataReader["sum"]);
        total_matches = Convert.ToInt32(dataReader["count"]);
    } 
    else 
    {
        //nothing was read, handle that case
    }
}

Conn.Close();

EDIT:

Misunderstood what the OP was asking for, and I also didn't catch the '<>' error.

I'll still keep this answer here, just for reference code.

Answer 2

      Conn.Open();
            Command.CommandText = "Select SUM(c_qty) from COLLVAULT_COINS WHERE c_type <>'US Currency' AND c_type<>'World Currency' AND c_type<>'World Coins' AND c_listName = '" + activeCollection + "'";
            int total_1 = Convert.ToInt32(Command.ExecuteScalar());
            //total records
            lblcollectedcount.Text = Convert.ToString(total_1);
            Conn.Close();

I had to use <> as not equals to instead of !=