How to show the count of all items in cross joined table in SQL Server - sql

Question

I have a table that has all Items in the inventory, table called CI
CI has 2 columns (ProdID and Price), and it looks like this
ProdID Price
-------------
A8373 700
G8745 900
J7363 300
K7222 800
Y6311 350
I have another table for documents called Docs with columns DocID, CustID and InvoiceID.
DocID, CustID, InvoiceID
------------------------
1 1001 751
2 1001 752
3 1001 753
4 1002 831
5 1002 832
6 1003 901
7 1003 902
Another table for purchases called Purchase with DocID, ProdID, ProdSize.
In the same invoice, ProdID can be repeated as it can be in different sizes
DocID, ProdID, ProdSize
------------------------
1 A8373 41
1 A8373 42
1 A8373 43
1 G8745 35
1 G8745 36
2 A8373 44
2 A8373 45
Now I want to get the quantity of of products for all customer and invoice, but for highest priced products
So it should be like this
CustID, InvoiceID, ProdID, Quantity
-----------------------------------
1001 751 A8373 3
1001 751 G8745 2
1001 751 K7222 0
1001 752 A8373 2
1001 752 G8745 0
1001 752 K7222 0
and to show 0 for the products that do not exist in that invoice
I wrote this query, but it is extremely slow. I wonder if there is an easier fast way to get this results
DECLARE #Features AS TABLE
(
CustID varchar(100),
InvoiceID varchar(100)
INDEX IX3 CLUSTERED(CustID, InvoiceID),
ProdID varchar(100),
Quantity bigint
)
INSERT INTO #Features (CustID, InvoiceID, ProdID, Quantity)
SELECT
R.CustID, R.InvoiceID, T.ProdID, COUNT(*) AS Quantity
FROM
Docs R
CROSS JOIN
(SELECT TOP 1000 * FROM CIs ORDER BY Price DESC) C
INNER JOIN
Purchase T ON T.DocID = R.DocID
GROUP BY
R.CustID, R.InvoiceID, T.ProdID
SELECT TOP 100 *
FROM #Features
ORDER BY CustID, InvoiceID, ProdID
SELECT COUNT(*) FROM #Features
UPDATE F
SET Quantity = Cnt
FROM #Features F
INNER JOIN
(SELECT R.CustID, R.InvoiceID, COUNT(*) Cnt
FROM Purchase T
INNER JOIN Docs R ON T.DocID = R.DocID
GROUP BY R.CustID, R.InvoiceID ) X ON F.CustID = X.CustID
AND F.InvoiceID = X.InvoiceID
SELECT * FROM #Features

Answer 1

here is a way to do this. I filter out the 1000 products first and then perform the join as follows..
Also there isn't a need for update query, all could be obtained in the SQL itself.
Filter early join late
with top_product
as (select prodid,price, rownumber() over(order by price desc) as rnk
from ci
)
,invoice_product
as(select d.docid,d.custid,d.invoiceid,p.prodid
from top_product
join docs d
on 1=1
and rnk<=1000
)
select a.CustID, a.InvoiceID, a.ProdID,count(b.prodid) as qty
from invoice_product a
left join purchase b
on a.DocID=b.docid
and a.ProdID=b.prodid
group by a.CustID, a.InvoiceID, a.ProdID

Answer 2

You can use the DENSE_RANK as follows:
select CustID, InvoiceID, ProdID, sum(qty) as qty
from (select d.CustID, d.InvoiceID, ci.ProdID, p.prodid as qty,
dense_rank() over (order by ci.price desc) as rn
from ci cross join docs d
left join purchase p on d.docid = p.docid and ci.prodid = p.prodid) t
where rn <= 1000
group by CustID, InvoiceID, ProdID

Answer 3

Can you please try following SQL Select statement where I used Common Table Expression SQL CTEs
with topproducts as (
select top 3 ProdID from CI order by Price desc
), sales as (
select
CustID,
InvoiceID,
ProdId,
count(ProdId) as cnt
from (
select
d.CustID,
d.InvoiceID,
p.ProdId
from Docs d
inner join Purchase p
on p.DocID = d.DocID
where p.ProdId in (select ProdId from topproducts)
) t1
group by
CustID,
InvoiceID,
ProdId
)
select
t.*, isnull(ss.cnt,0) as Qty
from (
select
distinct s.CustID, s.InvoiceID, p.ProdId
from sales s, topproducts p
) t
left join sales ss on ss.InvoiceID = t.InvoiceID and ss.ProdId = t.ProdId