Ranking functions and Joins - sql

Question

I have the following tables.
Order_det
Ord_num
item_code
Unit_sales_price
1111
1
50
1111
2
40
1111
3
30
1111
4
20
1111
5
10
2222
3
30
Pick_det
Ord_num
Shipment_num
Item_code
Qty_to_pick
Qty_picked
1111
1
1
100
100
1111
2
1
100
100
1111
3
2
100
100
2222
3
3
200
200
I want the table as follows,
Ord_num
Shipment_num
Item_code
Qty_to_pick
Qty_picked
Unit_sales_price
Total_price (Unit_sales_price*Qty_picked)
1111
3
2
100
100
40
4000
2222
3
3
200
200
30
6000
With the help of this community, I found a very similar answer i.e,
Link to that answer, Similar question
select *
from
(
select t1.*, max(shipment_num) over (partition by ord_num) as orders_max_ship_num
from pick_det t1
) with_max
where shipment_num = orders_max_ship_num
order by ord_num, item_code;
My question is,
where do I join the Order_det table to get the Unit_sales_price value to the already retrieved max shipment_num rows from pick_det table?

Answer 1

Im late to the party, as I typed everything up and made sure it ran correctly
if OBJECT_ID('tempdb..#Order_det') IS NOT NULL DROP TABLE #Order_det;
if OBJECT_ID('tempdb..#Pick_det') IS NOT NULL DROP TABLE #Pick_det;
CREATE TABLE #Order_det (Ord_num INT, item_code INT, Unit_sales_price INT);
CREATE TABLE #Pick_det(Ord_num INT, Shipment_num INT, Item_code INT, Qty_to_pick INT, Qty_picked INT);
INSERT INTO #Order_det (Ord_num, item_code, Unit_sales_price)
VALUES
(1111, 1, 50),
(1111, 2, 40),
(1111, 3, 30),
(1111, 4, 20),
(1111, 5, 10),
(2222, 3, 30)
INSERT INTO #Pick_det (Ord_num, Shipment_num, Item_code, Qty_to_pick, Qty_picked)
VALUES
(1111, 1, 1, 100, 100),
(1111, 2, 1, 100, 100),
(1111, 3, 2, 100, 100),
(2222, 3, 3, 200, 200)
SELECT
OrderDet.Ord_num
, PickList.Shipment_Num
, OrderDet.Item_code
, PickList.Qty_to_pick
, PickList.Qty_picked
, OrderDet.Unit_sales_price
, OrderDet.Unit_sales_price * PickList.Qty_picked AS Total_price
FROM
(
SELECT
Ord_num
, MAX(Shipment_num) OVER (PARTITION BY ord_num) AS MaxShipment_Num--
, Shipment_num
, Item_code
, Qty_to_pick
, Qty_picked
FROM #Pick_det
) AS PickList
INNER JOIN #Order_det AS OrderDet
ON OrderDet.Ord_num = PickList.Ord_num
AND OrderDet.item_code = PickList.Item_code
and PickList.Shipment_num = PickList.MaxShipment_Num

Answer 2

You can simply base a query on yours:
with s as
(
select *
from
(
select t1.*, max(shipment_num) over (partition by ord_num) as orders_max_ship_num
from pick_det t1
) with_max
where shipment_num = orders_max_ship_num
)
select
s.ord_num, s.shipment_num, s.item_code, s.qty_to_pick, s.qty_picked,
od.unit_sales_price, od.unit_sales_price * s.qty_picked as total_price
from s
join order_det od on od.ord_num = s.ord_num and od.item_code = s.item_code
order by s.ord_num, s.item_code;
Or you apply the join right away:
select
s.ord_num, s.shipment_num, s.item_code, s.qty_to_pick, s.qty_picked,
od.unit_sales_price, od.unit_sales_price * s.qty_picked as total_price
from
(
select t1.*, max(shipment_num) over (partition by ord_num) as orders_max_ship_num
from pick_det t1
) s
join order_det od on od.ord_num = s.ord_num and od.item_code = s.item_code
where s.shipment_num = s.orders_max_ship_num
order by s.ord_num, s.item_code;

Answer 3

Another simple technique you could use is by applying analytic function - Dense_Rank which is a window function that assigns a rank to each row within a partition of a result set
I am trying to rank by shipment_num in descending order and then just JOINing on the common column. I have used CTE and sub-query as well:
With temp AS(Select * from (SELECT a.*, dense_rank() OVER (PARTITION BY ord_num order by shipment_num desc) rnk
from Pick_det a) t where rnk = 1)
Select temp.Ord_num, temp.Shipment_num, temp.item_code, temp.Qty_to_pick, temp.Qty_picked,
temp.qty_to_pick * Order_det.Unit_sales_price total_price
from temp JOIN Order_det on temp.ord_num = Order_det.ord_num
AND temp.item_code = Order_det.item_code;
Your Sub-query would look something like this:
Select temp.Ord_num, temp.Shipment_num, temp.Item_code, temp.Qty_to_Pick, temp.Qty_picked,
temp.qty_to_pick * Order_det.Unit_sales_price total_price
from
(SELECT a.*, dense_rank() OVER (PARTITION BY ord_num order by shipment_num desc) rnk
from Pick_det a) temp INNER JOIN Order_det on temp.ord_num = Order_det.ord_num
AND temp.item_code = Order_det.item_code
AND temp.rnk = 1;
If you want to learn about dense_rank function, here is the link
Here is the SQL Fiddle