Dataset from two set of tables based on condition

Question

I have two queries that will return same columns from two different set of tables ( column mapping has been taken care of). The return type is out ref cursor. (P_SUPPLY_REORDER )
Query 1-SO
select
so.SMO_NO,
so.SPLY_ORD_DT,
so.fk_CUST_ID as CUST_ID,
so.CUST_PO_NO,
so.ATTENTION_NAME,
sum(sol.SPLY_ORD_QTY) as SPLY_ORD_QTY,
--sum(sol.sply_shp_qty),
so.ST_NAME,
so.ADDR_LN_2,
so.ADDR_LN_3,--sta.SHIP_TO_ADDRESS_LINE_3,
so.CITY_NAME,
so.ST_TERR_CD,
so.ZIP_CD,
so.SPCL_SHP_INSTR_TXT,
so.SHP_CNFRM_DT
,XCOM_ORDER_NO
from
supply_order so,
supply_order_line sol,
XCOM_ORDER_HEADER
where
so.FK_CUST_ID =in_cust_id
and so.pc_ord_no = sol.fk_pc_ord_no and
XCOM_ORDER_HEADER.FK_PC_ORD_NO = so.PC_ORD_NO
group by so.SMO_NO, so.SPLY_ORD_DT, so.fk_CUST_ID,
so.CUST_PO_NO, so.ATTENTION_NAME,
so.ST_NAME, so.ADDR_LN_2, so.ADDR_LN_3, so.CITY_NAME, so.ST_TERR_CD,
so.ZIP_CD, so.SPCL_SHP_INSTR_TXT, so.SHP_CNFRM_DT, XCOM_ORDER_NO;
Query-2 Xcom
select
null as sMO_NO,
xso.created_date as SPLY_ORD_DT,
xso.fk_cust_id as cust_id,
cust.cust_po_no as cust_PO_NO
,(sta.SHIP_TO_ATTN_FIRST_NAME||''||sta.SHIP_TO_ATTN_LAST_NAME) as attention_name,
xsol.CARTONS_ORDERED as SPLY_ORD_QTY,
--sum(sol.sply_shp_qty),
sta.SHIP_TO_ADDRESS_LINE_1 as ST_NAME,
sta.SHIP_TO_ADDRESS_LINE_2 as ADDR_LN_2,
--sta.SHIP_TO_ADDRESS_LINE_3,
NULL as ADDR_LN_3,
sta.ship_to_city as CITY_NAME,
sta.SHIP_TO_STATE as ST_TERR_CD,
sta.SHIP_TO_POSTAL_CODE as ZIP_CD,
sta.SHIPPING_INSTRUCTIONS as SPCL_SHP_INSTR_TXT,
null  as SHP_CNFRM_DT,
xso.XCOM_ORDER_NO as XCOM_ORDER_NO
from
XCOM_ORDER_HEADER xso,
XCOM_ORDER_LINES xsol,
customer cust,
ship_to_address sta
where
cust.cust_id = xso.fk_cust_id and
sta.fk_cust_id = xso.fk_cust_id
and xso.FK_CUST_ID =in_cust_id
and xso.FK_PC_ORD_NO is null
and xso.xcom_order_no = xsol.fk_xcom_order_no;Now the requirement is
One of four conditions are possible for each Supply Reorder Number:
•     Both table queries return no records
-     Populate all the P_SUPPLY_REORDER output fields with nulls
•     SUPPLY_ORDER returns a record, but XCOM_ORDER_HEADER returns no records
-     Populate output fields with values from the join of SUPPLY_ORDER and SUPPLY_ORDER_LINE.
•     SUPPLY_ORDER returns no records, but XCOM_ORDER_HEADER returns one record
-     Populate output fields with values from the join of XCOM_ORDER_HEADER and XCOM_ORDER_LINES.
•     SUPPLY_ORDER returns a record, and XCOM_ORDER_HEADER returns a record; find out the latest order by comapring max(SPLY_ORD_DT)
from SUPPLY_ORDER with max(CREATED_DATE) from XCOM_ORDER_HEADER.
-     If the latest order is in SUPPLY_ORDER, then populate output fields with values from the join of SUPPLY_ORDER and SUPPLY_ORDER_LINE.
-     If order dates are equal from both join results, then populate output fields with values from the join of SUPPLY_ORDER and SUPPLY_ORDER_LINE.
-     If the latest order is in XCOM_ORDER_HEADER, then populate output fields with values from the join of XCOM_ORDER_HEADER and XCOM_ORDER_LINES.
Question is how can we switch over the queries to pull respective dataset based on these conditions ( checking that which table join is going to return a row and then based upon latest order if both tables return a row) and all this logic as part of single SQL statement that is returned as OUT Ref Cursor.
Your help will be really appreciated. Thanks much in advance.

Answer 1

It would be easier if you would supply a dataset we can work with. And I assume the queries are called within a other cursor which returns in_cust_id right?
The best/fasters way would be to say goodbye to nested cursors.
You need:
the in_cust_id_query
extend SUPPLY_ORDER with a new field
max(CREATED_DATE) over (partiontion by cust_id) max_created_dateextend XCOM_ORDER_HEADER with a new field
max(SPLY_ORD_DT)over (partiontion by cust_id) max_sply_ord_dateThen you make a 3 level SELECT
the innerst () join all 3 sources
the second level names the rule
the outermost level applies the rule to each field:
SELECT
-- case statement to each field:
CASE rule
WHEN 1 THEN null
WHEN 2 THEN s_smo_no
WHEN 3 .... END  SMO_NO,
SELECT
-- check all rules:
case
--• Both table queries return no records
when s_in_cust_id IS NULL and h_in_cust_id IS NULL then 1
--• SUPPLY_ORDER returns a record, but XCOM_ORDER_HEADER returns no records
when s_in_cust_id IS NOT NULL and h_in_cust_id IS NULL then 2
--• SUPPLY_ORDER returns no records, but XCOM_ORDER_HEADER returns one record
when s_in_cust_id IS NULL and h_in_cust_id IS NOT NULL then 3
ELSE 4 end rule_id,
i.*
(SELECT c.in_cust_id,
             s.*, (with alias of course eg. s_...)
            h.*, (with alias of course  e.g. h_...)
from  in_cust_id_query c
  LEFT JOIN SUPPLY_ORDER s
   on (c.in_cust_id = s.in_cust_id)
LEFT XCOM_ORDER_HEADER h
  on (c.in_cust_id = h.in_cust_id) i;I hope you get it.
Of course you can do what you probable currently do. Open both cursors one by one and compare the results. But when you have 10000 in_cust_ids you start 20000 queries and you have a lot of code.
This method I'm showing need these roles coded as well, but you'll have ONE single query and that will be as fast as ORACLE can be. And I believe it's easier to read too. (But not simple!)
If you need more help, try to supply an example we can work on.
-- andy