I want to find the customer with the highest sales for each category.
Because i have to make seven queries to get the customer with the highest sales for each category by using the method below.
Instead of making two or more queries by changing the where c.cat_id in each queries, can i get the result using only one queries?
If yes, can someone please tell me how by correcting my code?

select c.cat_id, s.cust_id, cu.cust_fname, cu.cust_lname, sum((sd.sales_price * sd.quantity)) as Total
from product p, sales_detail sd, sales s, category c, brand b, customer cu
where sd.sales_id=s.sales_id and p.prod_id=sd.prod_id and c.cat_id=b.brand_cat and p.prod_brand = b.brand_id and s.cust_id=cu.cust_id and year(s.sales_date) between '1999' and '2003' and c.cat_id=1
group by s.cust_id
order by Total desc
limit 1;

select c.cat_id, s.cust_id, cu.cust_fname, cu.cust_lname, sum((sd.sales_price * sd.quantity)) as Total
from product p, sales_detail sd, sales s, category c, brand b, customer cu
where sd.sales_id=s.sales_id and p.prod_id=sd.prod_id and c.cat_id=b.brand_cat and p.prod_brand = b.brand_id and s.cust_id=cu.cust_id and year(s.sales_date) between '1999' and '2003' and c.cat_id=2
group by s.cust_id
order by Total desc
limit 1;

If you are executing sql from php then
You can generate the sql string dynamically through coding like following:

$sqlstr = "select c.cat_id, s.cust_id, cu.cust_fname, cu.cust_lname,
sum((sd.sales_price * sd.quantity)) as Total
from product p, sales_detail sd, sales s, category c, brand b, customer cu
where sd.sales_id=s.sales_id and p.prod_id=sd.prod_id and c.cat_id=b.brand_cat and p.prod_brand = b.brand_id and s.cust_id=cu.cust_id and year(s.sales_date) between '1999' and '2003' and c.cat_id = ";

$sqlstr .= $catid;

$sqlstr .= " group by s.cust_id
order by Total desc
limit 1";[/blue]