Oracle Database - 2 columns A (date) and B numbers 1-10, no dates must duplicate per number

I need to return the dates in column A that are replicated on any same number in column B
for example 2 records both with the same date in ColA and number in column B

Could it be as simple as doing a group by?

Select count(*), BNumber, ADate from YourTable group by BNumber, ADate order by BNumber, ADate

or maybe

Select distinct BNumber, ADate from YourTable order by BNumber, ADate

or maybe

Select ADate, BNumber from YourTable1 where not exists
(

select  GoodOnes.ADate, GoodOnes.BNumber from

( select count(*), t1.ADate, t1.BNumber from YourTable t1, YourTable t2
where t1.BNumber=t2.BNumber  and t1.ADate=t2.ADate
GROUP BY t1.ADate, t1.BNumber, t2.ADate, t2.BNumber
HAVING count(*)>0
order by t1.BNumber, t1.ADate  )  GoodOnes

)