If you have columns from A-F, include all those.
select ID,A as EntryVal from YourTable union all
select ID,B as EntryVal from YourTable union all
select ID,C as EntryVal from YourTable union all
select ID,D as EntryVal from YourTable union all
select ID,E as EntryVal from YourTable union all
select ID,F as EntryVal from YourTable