sql - Count records with a criteria like "within days" -

i have table below on sql.

orderid account  ordermethod     orderdate  dispatchdate  dispatchmethod  2145     qaz     14              20/3/2011  23/3/2011     2 4156     aby     12              15/6/2011  25/6/2011     1 

i want count records have reordered 'within 30 days' of dispatch date dispatch method '2' , ordermethod '12' , has come same account.

i want ask if can achieved 1 query or need create different tables , in stages think wll have now? please can code/query?

many t

try following, replacing [tablename] name of table.

select count(originalorders.orderid) [total_orders] [tablename] originalorders   inner join [tablename] reorders   on originalorders.account = reorders.account   , originalorders.orderdate < reorders.orderdate   , datediff(day, originalorders.dispatchdate, reorders.orderdate) <= 30   , reorders.dispatchmethod = '2'   , reorders.ordermethod = '12'; 

by using inner join you'll sure grab orders meet criteria.
linking 2 tables (which same table using aliases) make sure orders under same account counted.
results join further filtered based on criteria mentioned requiring orders have been placed within 30 days of dispatch date of previous order.