your Query will return N number of records so here is a solution i am adding
you have to execute your query and capture the result in datareader
SqlDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
ordre_linie_id= Convert.ToInt64(reader["ordre_linie_id"]);
}
reader.Close();
then you will have to implement for loop .....???
if you want to implement for single record then please specify where condition in your Query.