Join with alternating possibilities - sql

Question

There is a Select statement
Select i.ItemID, s.Price, s.Qty, s.Company From Item i
Inner Join Sku s ON s.ItemID = i.ItemID
Which returns this:
ItemID | Price | Qty | Company
1 | $50.00 | 0 | Abc inc.
1 | $45.00 | 5 | Def inc.
1 | $35.00 | 15 | Xyz inc.
2 | $36.00 | 4 | Abc inc.
2 | $45.00 | 5 | Def inc.
2 | $35.00 | 1 | Xyz inc.
3 | $20.00 | 2 | Abc inc.
3 | $45.00 | 0 | Def inc.
3 | $35.00 | 5 | Xyz inc.
But there needs to be the following logic:
Show the row with the lowest Price and Qty > 0, including the referring Company to that Result.
Else...
Show the row with the lowest price, including the referring Company to that Price.
Which would look something like this:
ItemID | Price | Qty | Company
1 | $35.00 | 15 | Xyz inc.
2 | $35.00 | 1 | Xyz inc.
3 | $20.00 | 2 | Abc inc.
I haven't tried anything because I honestly don't know what to try or what to even ask in my question. Any suggestions?

Answer 1

Here is one way to do it:
SELECT I.ItemId
, S.Price
, S.Qty
, S.Company
FROM dbo.Item I
CROSS APPLY (
SELECT MIN(Price) Price
FROM dbo.Sku MP
WHERE I.ItemId = MP.ItemId
AND Qty > 0
) MP
CROSS APPLY (
SELECT
TOP 1 Price
, Qty
, Company
FROM dbo.Sku S
WHERE S.ItemId = I.ItemId
AND S.Price = MP.Price
) S

Answer 2

How about something like this, using row number:
select
i.ItemId, s.Price, s.Qty, s.Company
from
item i
inner join
(
select
t.ItemId,
t.Price,
t.Qty,
t.Company,
RowNumber = row_number() over (PARTITION BY t.ItemId order by t.price asc, t.qty desc)
from
Sku t
) s on s.itemid = i.ItemId
where
s.RowNumber = 1
The row numbers "partition by" and "order by" are important here to ensure the correct results and this works even if all quantities for an item are 0.

Answer 3

Here is the query,
Select i.ItemID, s.Price, s.Qty, s.Company
From Item i
Inner Join Sku s
ON s.ItemID = i.ItemID
Inner Join (
select min(price) as Price, ItemID
from Sku
where Qty > 0
group by ItemId
)a
on a.ItemId = s.ItemId
and a.Price = s.Price
If you need only ItemId from Item table, you can remove the join with Item table itself as ItemId is present in Sku.

Answer 4

Select i.ItemID, min(s.Price) as price, s.Qty, s.Company From Item i
Inner Join Sku s ON s.ItemID = i.ItemID and s.qty>0
group by i.itemid, s.company, s.qty

Answer 5

Select i.ItemID, Min(s.Price) as Price, s.Qty, s.Company
From Item i Inner Join Sku s ON s.ItemID = i.ItemID
Where s.qty > 0
Group by i.itemid, s.qty, s.Company

Answer 6

Basically, you want the first sku record, ordered first by whether or not it has any stock (items with stock appearing first), and then by price, ascending. In the following query the common table expression returns the required SKU fields, along with the RowNum calculated field. RowNum is partitioned by ItemID (i.e. resets to 1 for each new ItemID) and ordered by the presence of stock first, and then by price. The main query then selects the first record from each ItemID:
WITH cte AS (
SELECT ItemID, Price, Qty, company,
ROW_NUMBER() OVER (PARTITION BY ItemId ORDER BY
CASE WHEN Qty > 0 THEN 1 ELSE 0 END DESC, Price ASC) AS RowNum
FROM #sku
)
SELECT ItemID, price, qty, Company FROM cte WHERE RowNum = 1