How to get Newest record with particular status?

[pelajhia]

I have two tables, table A contains date, type & transid
table B contains invoiceid and transid.

I need to get a count of invoices from table b by day where the newest transaction in table a is of type='M' (grouping by tableb.headerid).

My basic select to find transactions containing M types is:

select a.type, a.date, b.invoiceid
from
a, b
where a.transid=b.transid
and a.type='M'

After this point, it gets pretty foggy for me:

Throwing in a 'group by invoiceid' seems to keep me from being able to get the actual a.type from the table, rather I am forced to do something like count, etc.

eg:
select count(a.type), max(a.date), b.invoiceid
from a,b
where a.transid=b.transid
and a.type='M'
group by b.invoiceid

I was thinking I could create a loop to read through each grouping, but I'm just at a loss as to where to start. Any help would be greatly appreciated!!
Thanks.

 

[swampBoogie]

select a.type, a.date, cb.invoiceid
from
a ,  b as cb
where a.transid=cb.transid
and a.type='M'
and cb.headerid in (select max(headerid) from b
 where b.transid = cb.transid)