This is very useful advice for me from Hrishy

And check my previous query
SQL> SELECT MAX(YEAR_MON),MIN(YEAR_MON) FROM STOKCUMM;

MAX(YEAR_MON) MIN(YEAR_MON)
------------- -------------
200403 200001
real: 87265
The above is not using the index.

do this separately ,, it uses the index.

SQL> SELECT MIN(YEAR_MON) FROM STOKCUMM;

MIN(YEAR_MON)
-------------
200001
real: 47
SQL> SELECT MAX(YEAR_MON ) FROM STOKCUMM;

MAX(YEAR_MON)
-------------
200403
real: 31

or if we want them combined use hrishy's advice

select X.x,Y.y
from (
select min(YEAR_MON) x from STOKCUMM
)X,
(select max(YEAR_MON) Y from STOKCUMM
* )Y
> /

X Y
------ ---------
200001 200403

real: 16

Thanks