count and group by and order by in the same query

[phprock]

Post Table

post_id
post_threadid
post_member
post_date

thread Table

thread_id
thread_topicid
thread_member
thread_date

Topic Table

topic_id
topic_name

I want to display topic title,how many threads in that topic and the memberid and date of the last post or thread.

I want to use jOin Query..