Упростить UNION

SELECT IDobj,old_val1, new_val1 FROM ObjPars WHERE old_val1 <> new_val1
union
...
union
SELECT IDobj, old_valN, new_valN FROM ObjPars WHERE old_valN <> new_valN

CASE
 WHEN N=1 AND NOT EXISTS(SELECT Old_Val1 INTERSECT SELECT New_Val1) THEN Old_Val1
 WHEN N=2 AND NOT EXISTS(SELECT Old_Val2 INTERSECT SELECT New_Val2) THEN Old_Val2
.....
 WHEN N=<N> AND NOT EXISTS(SELECT Old_ValN INTERSECT SELECT New_ValN) THEN Old_ValN
 END OldValue,
CASE
 WHEN N=1 AND NOT EXISTS(SELECT Old_Val1 INTERSECT SELECT New_Val1) THEN New_Val1
 WHEN N=2 AND NOT EXISTS(SELECT Old_Val2 INTERSECT SELECT New_Val2) THEN New_Val2
.....
 WHEN N=<N> AND NOT EXISTS(SELECT Old_ValN INTERSECT SELECT New_ValN) THEN New_ValN
 END NewValue

--if object_id('tempdb..#ObjPars') is not null drop table #ObjPars
if object_id('tempdb..#ObjPars') is null begin
    create table #ObjPars (IDobj int, old_val1 float, new_val1 float, old_val2 float, new_val2 float, old_val3 float, new_val3 float, old_val4 float, new_val4 float)
    insert #ObjPars values (1,0,0,0,1,0,0,3,4),(2,0,0,0,0,0,0,0,0),(3,1,2,3,4,5,6,7,8)
end
 
;with cte as (
   select * 
   from #ObjPars o
   unpivot(val for name in (old_val1, new_val1, old_val2, new_val2, old_val3, new_val3, old_val4, new_val4))u
   )
select * 
from cte o
join cte n on n.IDobj=o.IDobj and n.name=REPLACE(o.name,'old','new') and n.val!=o.val
where o.name like 'old%'