Problems with CAST and order by

I have this problem:
This query is working:
select distinct cast(history.object_id as varchar(14)), object_assembly.object, history.center from history, object_assembly where history.object_id like '30210314%' and history.object_id = object_assembly.object_id

But I need to order the results by object_id, and it's not working. If I try simply to add
order by object_id
I get the following error message:
DB: ERROR: ORA-00918 column ambiguosly defined The same error I get if I add
order by cast(object_id as varchar(14))
while if i try
order by history.object_id
I get
DB: ERROR: ORA-01791 not a SELECTed expression

How to solve this ?

Thanks in advance,
Francesco Received on Thu Jan 16 2003 - 09:58:48 CST