slow mysql response

[uzwa ulhaque]

I am executing following query which returns a summary reports for the monthly sales of a local resturant, this query is taking up aroung 7 minutes:
any ideas on how to optimize it :-S

select oi.outlet_name Outlet, c.name Product, cd.name Deal,sum(dt.qty) qty, sum(dt.total_price) total_price from Detail_Table dt, Order_Status os, Category c, Category_Detail cd, Outlet_Information oi where dt.order_id = os.order_id and dt.Category_id = c.Category_id and dt.Category_Detail_id = cd.Category_Detail_id and os.outlet_id = oi.outlet_id and dt.order_date between '2005-09-01' and '2005-09-20' group by oi.outlet_name, c.name , cd.name order by 1,2,3 desc