GRPO Stored Procedure Block for Cost Discrepancy

Question

Dear Experts,
I am in the process of writing a stored procedure to block a GRPO from posting if one of the items' prices has a 30% discrepancy on item cost.
I couldn't use AvgPrice as the value in the table considers the transaction being processed. What I am trying to do is compare the price with the previous GRPO's price done for this item.
Any other suggestions would be great.
Now this works fine until I add a second item on the document or even the same item twice. It will only apply block to item on first row.
SP will only block first row in example below:
#1 Item A 50.00
#2 Item B 100.00
#3 Item A 10.00
I was wondering how the block can look at the individual lines, alternatively has anyone done something similar that can help me.
Query:
--Block Goods Receipt PO with 30% Price Discrepancy
declare @item nvarchar(255)
select @item = NULL
IF @TRANSACTION_TYPE = 'A' AND @OBJECT_TYPE = '20'
BEGIN
Select @item = A.ItemCode
From
               (SELECT 'itemcode' =
                    CASE --greater than
                         When (((T1.Price -
                                   --fetch prev price
                                   (SELECT max(b.price)
                                   from opdn a inner join pdn1 b on a.DocEntry = b.docentry
                                   where b.ItemCode = T1.itemcode AND
                                   a.DocNum =
                                   (SELECT MAX(a1.Docnum) from OPDN a1 inner join PDN1 b1 on a1.DocEntry = b1.DocEntry
                                   WHERE b1.ItemCode = b.ItemCode
                                   AND a1.docnum <
                                             (SELECT MAX(a2.Docnum) from OPDN a2 inner join PDN1 b2 on a2.DocEntry = b2.DocEntry
                                             WHERE b2.ItemCode = b1.ItemCode)
                                   --##fetch prev price     
                                   --fetch prev price
                                   (SELECT max(b.price)
                                   from opdn a inner join pdn1 b on a.DocEntry = b.docentry
                                   where b.ItemCode = T1.Itemcode AND
                                   a.DocNum =
                                        (SELECT MAX(a1.Docnum) from OPDN a1 inner join PDN1 b1 on a1.DocEntry = b1.DocEntry
                                        WHERE b1.ItemCode = b.ItemCode
                                        AND a1.DocNum < (
                                        (SELECT MAX(a2.Docnum) from OPDN a2 inner join PDN1 b2 on a2.DocEntry = b2.DocEntry
                                             WHERE b2.ItemCode = b1.ItemCode)
                                   --##fetch prev price     
                                   ) * 100) >= 30
                              Then T1.ItemCode
                              --smaller than
                              When (((T1.Price -
                                   --fetch prev price
                                   (SELECT max(b.price)
                                   from opdn a inner join pdn1 b on a.DocEntry = b.docentry
                                   where b.ItemCode = T1.itemcode AND
                                   a.DocNum =
                                   (SELECT MAX(a1.Docnum) from OPDN a1 inner join PDN1 b1 on a1.DocEntry = b1.DocEntry
                                   WHERE b1.ItemCode = b.ItemCode
                                   AND a1.docnum <
                                             (SELECT MAX(a2.Docnum) from OPDN a2 inner join PDN1 b2 on a2.DocEntry = b2.DocEntry
                                             WHERE b2.ItemCode = b1.ItemCode)
                                   --##fetch prev price     
                                   --fetch prev price
                                   (SELECT max(b.price)
                                   from opdn a inner join pdn1 b on a.DocEntry = b.docentry
                                   where b.ItemCode = T1.Itemcode AND
                                   a.DocNum =
                                        (SELECT MAX(a1.Docnum) from OPDN a1 inner join PDN1 b1 on a1.DocEntry = b1.DocEntry
                                        WHERE b1.ItemCode = b.ItemCode
                                        AND a1.DocNum < (
                                        (SELECT MAX(a2.Docnum) from OPDN a2 inner join PDN1 b2 on a2.DocEntry = b2.DocEntry
                                             WHERE b2.ItemCode = b1.ItemCode)
                                   --##fetch prev price     
                                   ) * 100) <= -30
                              Then T1.ItemCode
                              end
                    FROM [DBO].[OPDN] T0 INNER JOIN [DBO].[PDN1] T1 ON T0.DocEntry = T1.DocEntry INNER JOIN OITM T2 on T1.ItemCode = T2.Itemcode     
                    --AND NOT T0.UserSign = 1 --Manager
                    AND T1.DOCENTRY = @LIST_OF_COLS_VAL_TAB_DEL) A
IF EXISTS
(Select @item where @item is not NULL)
     BEGIN
          SELECT @ERROR = 2, @ERROR_MESSAGE = 'Price Discrepancy too large. Please check item:' + ' ' + @item
     END
END
Thanks,
Adriaan

Answer 1

That's a really tough form to create.
Here's a couple of dynamic forms you can try out:
By Francois Degrelle:   "DYNAMIC_FORM.fmb".
And my old dynamic matrix Form is here:   QA: Quick Access  An Oracle Forms dynamic utility form