Question

i want to know what is the wrong in this query I want to select all rows for 1 column

 string command = "select money from User_Data";
 SqlCommand update_money = new SqlCommand(command, con_string.con);
 SqlDataReader money_reader;
 money_reader = update_money.ExecuteReader();

Answer 1

You’re on the right track – now once you have the data reader, you need to iterate over the rows:

string command = "select money from User_Data";

SqlCommand update_money = new SqlCommand(command, con_string.con);
SqlDataReader money_reader = update_money.ExecuteReader();

List<decimal> _allValues = new List<decimal>();

while(money_reader.Read())
{
    _allValues.Add(money_reader.GetDecimal(0));
}

This assumes your money column would be of type decimal(x,y) or money on SQL Server.