My solution is to select all rows from the database, and filter down the rows in .NET if a parameter was passed in. This could become troublesome if there were a large number of jobs, although I suppose I'd move to a real database if that ever happens.
private static string _dbJobSelect = "SELECT jID, jAddress FROM Job";
public static DataTable GetJobs(string jAddress)
{
DataTable dt = ExecuteDataTable(_dbJobSelect);
if (!string.IsNullOrEmpty(jAddress))
{
DataView dv = dt.DefaultView;
dv.RowFilter = string.Format("jAddress = '{0}'", jAddress);
dt = dv.ToTable();
}
return dt;
}