left join e count: una query difficile

[stabi]

prova con

select 'a' as tipo,count(*) as tot, curdate() as data from Fpost where post_stanza='$stanza' and post_relativo_a=0
union all
select 'b' as tipo,count(*) as tot, curdate() as data from Fpost where post_stanza='$stanza' and post_relativo_a!=0
union all
select username as tipo,post_id as tot,post_data_post as data 
from Fpost,users where post_stanza='$stanza' and post_autore=user_id 
order by post_id desc