// Connect to the database
// ... 

var command = conn.CreateCommand();
command.CommandText = @"
  SELECT
    Language, Percentage
  FROM countrylanguage
  WHERE 
    CountryCode = @Code AND
    Percentage > @Percent";
command.Parameters.Add("@Code", MySqlDbType.VarChar).Value = "RUS";
command.Parameters.Add("@Percent", MySqlDbType.Float).Value = 1;
var reader = command.ExecuteReader();

// Get all rows
while (reader.Read())
{
    WriteLine(reader.GetString(0) + ": " +
        reader.GetFloat("Percentage"));
}

// Close the connection
conn.Close();