Counting duplicate items in different order - sql-server

Question

Goal:
To know if we have purchased duplicate StockCodes or Stock Description more than once on difference purchase orders
So, if we purchase Part ABC on Purchase Order 1 and Purchase Order 2, it should return the result of
PurchaseOrders, Part#, Qty
Purchase Order1, Purchase Order2, ABC, 2
I just don't know how to pull the whole code together, more to the point, how do I know if it's occurred on more than 1 Purchase Order without scrolling through all the results , may also have to do with Multiple (Having Count) Statements as I only seem to be doing by StockCode
SELECT t1.PurchaseOrder,
t1.MStockCode,
Count(t1.MStockCode) AS SCCount,
t1.MStockDes,
Count(t1.MStockDes) AS DescCount
FROM PorMasterDetail t1
INNER JOIN PorMasterHdr t2
ON t1.PurchaseOrder = t2.PurchaseOrder
WHERE Year(t2.OrderEntryDate) = Year(Getdate())
AND Month(t2.OrderEntryDate) = Month(Getdate())
GROUP BY t1.PurchaseOrder,
t1.MStockCode,
t1.MStockDes
HAVING Count(t1.MStockCode) > 1
Using responses I came up with the following
select * from
(
SELECT COUNT(dbo.InvMaster.StockCode) AS Count, dbo.InvMaster.StockCode AS StockCodes,
dbo.PorMasterDetail.PurchaseOrder, dbo.PorMasterHdr.OrderEntryDate
FROM dbo.InvMaster INNER JOIN dbo.PorMasterDetail ON
dbo.InvMaster.StockCode = dbo.PorMasterDetail.MStockCode
INNER JOIN dbo.PorMasterHdr ON dbo.PorMasterDetail.PurchaseOrder = dbo.PorMasterHdr.PurchaseOrder
WHERE YEAR(dbo.PorMasterHdr.OrderEntryDate) = YEAR(GETDATE())
GROUP BY dbo.InvMaster.StockCode, dbo.InvMaster.StockCode,
dbo.PorMasterDetail.PurchaseOrder, dbo.PorMasterHdr.OrderEntryDate
) Count
Where Count.Count > 1
This returns the below , which is starting to be a bit more helpful
In result line 2,3,4 we can see the same stock code (*30044) ordered 3 times on different
purchase orders.
I guess the question is, is it possible to look at If something was ordered more than once within say a 30 day period.
Is this possible?
Count StockCodes PurchaseOrder OrderEntryDate
2 *12.0301.0021 322959 2014-09-08
2 *30044 320559 2014-01-21
8 *30044 321216 2014-03-26
4 *30044 321648 2014-05-08
5 *32317 321216 2014-03-26
4 *4F-130049/TEST 323353 2014-10-22
5 *650-1157/E 322112 2014-06-24
2 *650-1757 321226 2014-03-27

Answer 1

SELECT *
FROM
(
SELECT h.OrderEntryDate, d.*,
COUNT(*) OVER (PARTITION BY d.MStockCode) DupeCount
FROM
PorMasterHdr h
INNER JOIN PorMasterDetail d ON
d.PurchaseOrder = h.PurchaseOrder
WHERE
-- first day of current month
-- http://blog.sqlauthority.com/2007/05/13/sql-server-query-to-find-first-and-last-day-of-current-month/
h.OrderEntryDate >= CONVERT(VARCHAR(25), DATEADD(dd,-(DAY(GETDATE())-1),GETDATE()),101)
) dupes
WHERE
dupes.DupeCount > 1;
This should work if you're only deduping on stock code. I was a little unclear if you wanted to dedupe on both stock code and stock desc, or either stock code or stock desc.
Also I was unclear on your return columns because it almost looks like you're wanting to pivot the columns so that both purchase order numbers appear on the same line.