Complex query design suggestions

Question

Hi, I should first of all point out I'm new to pl/sql and struggling a bit so any help you can provide is really appreciated.
I have the requirements for a complex query the conditions of which are as follows
Four tables involved
ProductGroups, Products, Stock, StockMovements
Query requirements psudeocode (broken into bits to make things easier)
/* CODE */
Select distinct products
where productgroup.group between 'a' and 'z'
And stock.location = 'x'
And stock.qty > 0
For each product
     _myDate = currentdate - 1 year
     stkMvt= Select * from StockMovements where product = product
     If(select count(*) from stkMvt where code = 'A' and type = 'A' and source = 'A' and stkMvt.date > _myDate) > 0)
          -- exclude row / move next product
     End If
     If (select count(*) from stkMvt where code = 'B' and type = 'B' and source = 'B' and stkMvt.date> _myDate) > 0)
          -- exclude row / move next product
     End If
     If (select count(*) from stkMvt where code = 'C' and type = 'C' and source = 'C' and Qty > 0 and stkMvt.date> _myDate) > 0)
          -- exclude row / move next product
     End If
     If (select max(stkMvt.date) from stkMvt where code = 'D' and type = 'D' and source = 'D' < _myDate)
          If ( select max(stkMvt.date) from stkMvt where ((code = 'E' and type = 'E' and source 'E')
               Or (code = 'F' and type = 'F' and source = 'F')
               Or (code = 'G' and type = 'G' and source = 'G')) > _myDate )
               -- exclude row / move next product
          End If
     End If
     -- Get the fields to return
     Qty1 = Select coalesce(sum(qty),0) from stkMvt where code = 'H' and type = 'H' and source = 'H'
     Qty2 = Select coalesce(sum(qty),0) from stkMvt where code = 'I' and type = 'I' and source = 'I'
     Qty3 = Select coalesce(sum(qty),0) from stkMvt where code = 'J' and type = 'J' and source = 'J' and stkMvt.date between :fromDate and :toDate
     LastDate = Select max(stkMvt.Date) from stkMvt
     StkQty = Select Qty from Stock where product = product
     AllQty = Select AllQty from Stock where product = product
     FreeQty = StkQty - AllQty
     Value = Select value from Stock
     Select group, product , Qty1, Qty2, Qty3, LastDate, StkQty, AllQty, FreeQty, Value INTO table/cursor
Loop
Return table / cursor
/* CODE END */
Any guidance about the best way to achieve the above in an SP or Package would be massively helpful,
Thanks in advance
Scott.

Answer 1

Agreed, it is a mess and I was looking the other way when it was dumped into my lap to deal with unfortunately. Any pointers in the right direction would really be helping me out.
ok first the table structures, I'll include only the relevant fields to make things a bit easier.
CREATE TABLE "TEST"."CMGROUP"
(     "CMGRP_GROUP" CHAR(4 BYTE),
     "CMGRP_DESC" CHAR(30 BYTE)
CREATE TABLE "TEST"."CMPROD"
(     "CMP_PRODUCT" CHAR(20 BYTE),
     "CMP_DESC" CHAR(50 BYTE),
     "CMP_GROUP" CHAR(4 BYTE),
     "CMP_SPECIAL" CHAR(1 BYTE)
CREATE TABLE "TEST"."STOCK"
     "STK_PRODUCT" CHAR(20 BYTE),
     "STK_LOC" CHAR(5 BYTE),
     "STK_STKQTY" NUMBER,
     "STK_VALUE" NUMBER,
     "STK_ALLSTK" NUMBER
CREATE TABLE "TEST"."STMOVE"
     "STMOV_LOC" CHAR(5 BYTE),
     "STMOV_PRODUCT" CHAR(20 BYTE),
     "STMOV_DATE" DATE,
     "STMOV_TYPE" CHAR(1 BYTE),
     "STMOV_SOURCE" CHAR(1 BYTE),
     "STMOV_CODE" CHAR(1 BYTE),
     "STMOV_QTY" NUMBER,
     "STMOV_YEAR" NUMBER(5,0),
     "STMOV_PERIOD" NUMBER(5,0)
Relationships are as follows
CMGROUP.CMGRP = CMPROD.CMP_GROUP (One to Many)
CMPROD.CMP_PRODUCT = STOCK.STK_PRODUCT (One to Many)
STOCK.STK_LOC = STMOVE.STMOV_LOC (Many to Many)
STOCK.STK_PRODUCT = STMOVE.STMOV_PRODUCT (Many to Many)
As for the requirements well they aren't straightforward but the gist of it is to return a ref cursor to a crystal report from an oracle package. The ref cursor is to contain the following
select products that are
1) In stock
2) For a specific location
3) In a range of product groups
4) That either have a manual stock receipt movement within the last 12 months
5) Or do not have the following stock movement within the last 12 months
     a. PO Receipt
     b. WO Receipt
     c. Stock Acquisition Receipt
Of the results I need to
     1) Display the group
     2) Display the product
     3) Sum the Qty of WO Receipts from the 1st of the month (13 Months Ago) until today
     4) Sum the Qty of PO Receipts from the 1st of the month (13 Months Ago) until today
     5) Sum the Qty of Stock Transfers from the 1st of the month (13 Months Ago) until today
     6) Display the most recent stock movement date
     7) Display the current stock quantity
     8) Display the allocated stock quantity
     9) Display the available stock quantity
     10) Display the stock value
Movement code definitions as follows     
Manual Stock Receipt
Stmov_type: O
Stmov_source: J
Stmov_code: G
Purchase Order Goods Receipt
Stmov_type: O
Stmov_source: R
Stmov_code: S
Stock Requisition Receipt (Positive stmov_qty value)
Stmov_type: G
Stmov_source: J
Stmov_code: L
Stock Requisition Issue (Negative stmov_qty value)
Stmov_type: G
Stmov_source: J
Stmov_code: L
Manual Stock Issue to GL Account (Issue to workshop)
Stmov_type: F
Stmov_source: J
Stmov_code: G
Works order issue
Stmov_type: F
Stmov_source: W
Stmov_code: G
Works order receipt
Stmov_type: 1
Stmov_source: W
Stmov_code: G
There are a few other conditions and requirements but I think that covers the basics. If there is anything I've left out let me know and I do my best to provide.
Thanks in advance
Scott.