- # return the first (only) column
- map { [ split(',',$_->[0]) ],
- [ split(',',$_->[1]) ] } @{ $sth->fetchall_arrayref };
+ # return a pair of entries for the null set (conventionally we use zero
+ # for that)
+ ( [ 0 ], [ '(empty class)' ],
+ # followed by the first two columns: report class numbers and names
+ map { [ split(',',$_->[0]) ],
+ [ split(',',$_->[1]) ] } @{ $sth->fetchall_arrayref }
+ );