SQL10 SQL Excercise, Requirement solution, Practice, Query Logic

Data in Table 

order_Day	order_id	prod_id	quantity	price
01-jul-2011	o1	p1	5	5
01-jul-2011	o2	p2	2	10
01-jul-2011	o3	p3	10	25
01-jul-2011	o4	p1	20	5
02-jul-2011	o5	p3	5	25
02-jul-2011	o6	p4	6	20
02-jul-2011	o7	p1	2	5
02-jul-2011	o8	p5	1	50
02-jul-2011	o9	p6	2	50
02-jul-2011	o10	p2	4	10

Output Needed

order_Day	prod_id	Sum
01-jul-2011	p3	250
02-jul-2011	p3	125

SELECT *
INTO SQL10
FROM (
	SELECT '01-jul-2011' order_Day
		,'o1' order_id
		,'p1' prod_id
		,5 quantity
		,5 price
	
	UNION ALL
	
	SELECT '01-jul-2011'
		,'o2'
		,'p2'
		,2
		,10
	
	UNION ALL
	
	SELECT '01-jul-2011'
		,'o3'
		,'p3'
		,10
		,25
	
	UNION ALL
	
	SELECT '01-jul-2011'
		,'o4'
		,'p1'
		,20
		,5
	
	UNION ALL
	
	SELECT '02-jul-2011'
		,'o5'
		,'p3'
		,5
		,25
	
	UNION ALL
	
	SELECT '02-jul-2011'
		,'o6'
		,'p4'
		,6
		,20
	
	UNION ALL
	
	SELECT '02-jul-2011'
		,'o7'
		,'p1'
		,2
		,5
	
	UNION ALL
	
	SELECT '02-jul-2011'
		,'o8'
		,'p5'
		,1
		,50
	
	UNION ALL
	
	SELECT '02-jul-2011'
		,'o9'
		,'p6'
		,2
		,50
	
	UNION ALL
	
	SELECT '02-jul-2011'
		,'o10'
		,'p2'
		,4
		,10
	) t

Solution 1

SELECT *
FROM (
	SELECT ps.order_day
		,ps.prod_id
		,accum_sum
		,row_number() OVER (
			PARTITION BY ps.order_day ORDER BY accum_sum DESC
			) rn
	FROM SQL10 ps
	JOIN (
		SELECT quantity * price total_amount
			,order_day
			,order_id
			,sum(quantity * price) OVER (
				PARTITION BY order_day
				,prod_id ORDER BY order_day
					,prod_id
				) accum_sum
		FROM SQL10
		) ps1 ON ps.order_day = ps1.order_day
		AND ps.order_id = ps1.order_id
	) t
WHERE rn = 1

Solution 2

SELECT Order_Day

	,PrOd_id
	,SOLD_AMT
FROM (
	SELECT Order_Day
		,PrOd_id
		,SUM(quantity * Price) SOLD_AMT
		,DENSE_RANK() OVER (
			PARTITION BY Order_DaY ORDER BY SUM(quantity * Price) DESC
			) RNK
	FROM SQL10
	GROUP BY Order_Day
		,PrOd_id
	) t1
WHERE RNK = 1;