help need it

hi everyone,

i've  got an oracle query that is something like this:

select id_mensagem, ds_description, e_mail, to_char(ds_date,'DD/MM/YY - 
HH24:MI'), assunto,
respondidas, mensagem, mensagens.id_resposta
from (select id_mensagem, ds_description, e_mail, ds_date, assunto, 
mensagem, id_resposta, RANK() OVER ( ORDER BY id_mensagem desc )as i from varForum where varForum.id_resposta
varIdComparator)mensagens, (select id_resposta, count(id_mensagem) respondidas from varForum group by id_resposta)
respostas
where mensagens.id_mensagem = respostas.id_resposta(+)
varRange
order by ds_date desc

now i need to pass the query to postgresql, does any one can help me.

best regards,

etur