Question

I have the following query which is returning 4 results when the table FI_CurrentReceiptData only has 2 rows. The extra rows are exact duplicates. I can use DISTINCT to fix, but my understanding is that this is bad practice and I would do better to find and correct the error (IS THIS CORRECT?).

Why is this query doubling the results?

All variables are declared elsewhere in a stored procedure and this query does return the needed fields.

SELECT ( (Select Max(ReceiptNumber)
          from   Avanti_InventoryReceipts) + CR.Seq ),
       CR.ItemNumber,
       Convert(char(8), GETDATE(), 112),
       PONum,
       'FL-INV',
       PH.POVendor,
       0,
       0,
       'O',
       CR.QtyOrdered,
       QtyReceivedToday,
       QtyReceivedToday,
       Case @closePO
         When 'N' Then Case
                         When ( QtyOrdered - QtyReceivedToday ) < 0 Then 0
                         Else ( QtyOrdered - QtyReceivedToday )
                       End
         When 'Y' Then 0
         Else 0
       End,
       PD.TransCost * QtyReceivedToday,
       IH.PriceWholeSale,
       IH.CostLast,
       QtyReceivedToday,
       0,
       '',
       PODetailDescription /* , .... More columns...*/

FROM   FI_CurrentReceiptData CR
       LEFT JOIN Avanti_PODetails PD
         ON CR.PONum = PD.PONumber
       LEFT JOIN Avanti_POHeader PH
         ON CR.PONum = PH.PONumber
       LEFT JOIN Avanti_InventoryHeader IH
         ON CR.ItemNumber = IH.ItemNumber  

NEW WHERE CLAUSE SOLUTION:

FROM FI_CurrentReceiptData CR
inner JOIN Avanti_PODetails PD ON CR.PONum = PD.PONumber AND CR.ItemNumber = PD.TransItem AND CR.QtyOrdered = PD.TransQty
left JOIN Avanti_POHeader PH ON PD.PONumber = PH.PONumber
left JOIN Avanti_InventoryHeader IH ON CR.ItemNumber = IH.ItemNumber

Answer 1

One of the joined tables has more than one matching row.
I cannot say for certain which one, but if I were you I’d start looking
at the Avanti_PODetails table. Does it have more than one matching record for any of the two receipts?