You have to create your own report which will print reports Category wise.

I mean in report 1st table will be for Category A with its Products and 2nd table for Category B with its Products.

Solve my issue for in create one method retrive data from postgrey and set in to rml that return dict.

def get_val(self, obj):
        query = """
           SELECT  categ_type as name, sum(product_uom_qty * price_unit) as total
           FROM sale_order_line 
           WHERE order_id = %s GROUP BY categ_type
        """%(obj.id)
        self.cr.execute(query)
        data = self.cr.dictfetchall()
        for t in data:
           dict={'name' : t['name'], 'total' : t['total']}
           res.append(dict)
        return res 

repeatIn[o.get_val(o), 'p']

[[ p['name'] ]] [[ p['total'] ]]