NULL values not found in cursor - oracle

Question

I am trying to:
Create a cursor that gets all the current prices of items in a store.
I bulk collect the cursor and loop upserting by using MERGE statement into STORE_INVENTORY table.
Now I want to NULL out the PRICE column in the STORE_INVENTORY table that are not in the cursor.
How can step 3 be done? I can do step 1 and 2 already as I have already updated or inserted the items that are pulled from the cursor.
Here is some example data:
There are three source tables where it is updated by an external party. My objective is to take these three sources of data and merge it into a singular table.
SOURCE TABLES
ITEM_TYPES
DESC_ID | TYPE
A | Kitchen
B | Bath
ITEM_MANIFEST
LOC_ID | ORIGIN
U | USA
C | CHINA
ITEM_PRICE
ITEM_ID | PRICE | DESC_ID | LOC_ID | DATE
0 | 3.99 | A | U | 9/11/2015
1 | 2.99 | B | C | 9/11/2015
2 | 1.99 | A | U | 9/05/2015
DESTINATION TABLE
STORE_INVENTORY
ITEM_ID | TYPE | ORIGIN | PRICE
0 | Kitchen | CHINA | 3.99
8 | Bath | USA | 2.99
So after I execute the SQL Procedure that has a date as a parameter. It will only pull from ITEM_PRICE if it's after the given date.
If execute the procedure with the passed in date 9/10/2015
Expected Output
STORE_INVENTORY
0 | Kitchen | USA | 3.99
1 | Bath | China | 2.99
8 | Bath | USA | NULL

Answer 1

So, something like this, then?
drop table item_description;
drop table item_manifest;
drop table item_price;
drop table store_inventory;
create table item_description
as
select 'A' desc_id, 'Kitchen' type from dual union all
select 'B' desc_id, 'Bath' type from dual;
create table item_manifest
as
select 'U' loc_id, 'USA' origin from dual union all
select 'C' loc_id, 'CHINA' origin from dual;
create table item_price
as
select 0 item_id, 3.99 price, 'A' desc_id, 'U' loc_id, to_date('11/09/2015', 'dd/mm/yyyy') dt from dual union all
select 1 item_id, 2.99 price, 'B' desc_id, 'C' loc_id, to_date('11/09/2015', 'dd/mm/yyyy') dt from dual union all
select 2 item_id, 1.99 price, 'A' desc_id, 'U' loc_id, to_date('05/09/2015', 'dd/mm/yyyy') dt from dual;
create table store_inventory
as
select 0 item_id, 'Kitchen' type, 'CHINA' origin, 3.99 price from dual union all
select 8 item_id, 'Bath' type, 'USA' origin, 2.99 price from dual;
select * from store_inventory;
ITEM_ID TYPE ORIGIN PRICE
---------- ------- ------ ----------
0 Kitchen CHINA 3.99
8 Bath USA 2.99
select coalesce(ip.item_id, si.item_id) item_id,
coalesce(id.type, si.type) type,
coalesce(im.origin, si.origin) origin,
ip.price
from item_description id
inner join item_price ip on (id.desc_id = ip.desc_id and ip.dt > to_date('10/09/2015', 'dd/mm/yyyy')) -- use a parameter for the date here
inner join item_manifest im on (ip.loc_id = im.loc_id)
full outer join store_inventory si on (si.item_id = ip.item_id);
ITEM_ID TYPE ORIGIN PRICE
---------- ------- ------ ----------
0 Kitchen USA 3.99
8 Bath USA
1 Bath CHINA 2.99
merge into store_inventory tgt
using (select coalesce(ip.item_id, si.item_id) item_id,
coalesce(id.type, si.type) type,
coalesce(im.origin, si.origin) origin,
ip.price
from item_description id
inner join item_price ip on (id.desc_id = ip.desc_id and ip.dt > to_date('10/09/2015', 'dd/mm/yyyy')) -- use a parameter for the date here
inner join item_manifest im on (ip.loc_id = im.loc_id)
full outer join store_inventory si on (si.item_id = ip.item_id)) src
on (src.item_id = tgt.item_id)
when matched then
update set tgt.type = src.type,
tgt.origin = src.origin,
tgt.price = src.price
when not matched then
insert (tgt.item_id, tgt.type, tgt.origin, tgt.price)
values (src.item_id, src.type, src.origin, src.price);
commit;
select * from store_inventory;
ITEM_ID TYPE ORIGIN PRICE
---------- ------- ------ ----------
0 Kitchen USA 3.99
8 Bath USA
1 Bath CHINA 2.99
Obviously, your procedure would have an input parameter of DATE datatype to pass into the query, and your query would use the parameter, rather than a hardcoded date like I did in my example. E.g. ip.dt > p_cutoff_date
I can do step 1 and 2 already as I have already updated or inserted
the items that are pulled from the cursor.
Hmm. These steps seem unnecessary - why not do them as part of the MERGE statement? What does the store_inventory table look like before you do your insert/update from the cursor? Also, what is the cursor you're using to do this?

Answer 2

couldn't you do a date-limited subselect of ITEM_PRICE.PRICE, after pulling in the TYPE and ORIGIN via the main join to ITEM_PRICE, without limiting on date?
i.e. something like.
select ITEM_ID, TYPE, ORIGIN
/* not selecting PRICE in the main join */
,(select PRICE from ITEM_PRICE where your join conditions
and DATE >= your param)
from ITEM_TYPES, ITEM_MANIFEST, ITEM_PRICE
where your join conditions, but no criteria on DATE
Sorry, would be clearer and easier to type up if you had provided your existing query.
From re-reading your question, I am unsure if you are inserting only 2 rows but want to get 3. Or if you have 3 rows, but you want to NULL out the missing price.
If the target table already has the 3 rows, then, instead of doing a CURSOR based approach (which can be slow on high volumes and is fussy to write), why not do an UPDATE instead, with DATE as a criteria? The NULL will be assigned to price if there is no match, that's how UPDATEs work.
UPDATE STORE_INVENTORY set PRICE
= (select PRICE from ITEM_PRICE where your join conditions
and DATE >= your param)