Oracle query with different dates - oracle

Question

I have to write this query, and it is a bit complex. I am hoping someone can help, as I've received much help from here before.
Say I have a customers stock portfolio. And a list of company tickers, and the date the ticker was purchased. My list looks something like this:
CYSL 1/16/2017
MCIG 4/1/2016
MSRT 9/13/2016
NTFU 1/16/2017
QNTM 10/30/2014
SIGWX 6/28/2014
TRMCX 6/25/2014
TRT2 4/19/2016
Now, in order for my to compute some YTD performance, I need to apply the following logic:
If the purchase date > 01/01/2017, I'll use the closing price of the ticker when it was purchased.
If the purchase date < 01/01/2017. I'll use the closing price of the ticker on <= 12/31/2016.
There are 2 tables involved: 1) Portfolio Table 2) Price History
I've gotten this far:
SELECT ticker, MIN(transaction_date) KEEP (DENSE_RANK FIRST ORDER BY transaction_date) transaction_date
FROM customer_portfolios
WHERE portfolio_id = 954118
GROUP BY ticker;
This gives me the list above. Now, I am lost on how to join this with the logic above, to get the proper date, and go after the proper price.
I hope I am explaining this correctly.
And help will be great, and I can explain more if it will help you, help me.
Thank you.

Answer 1

Use GREATEST to get the date at either 2016-12-31 or the later transaction date and then just join to the price history table:
SELECT cp.ticker,
cp.transaction_date,
h.close_price
FROM (
SELECT ticker,
GREATEST(
DATE '2016-12-31',
MIN(transaction_date) KEEP (
DENSE_RANK FIRST
ORDER BY transaction_date
)
) AS transaction_date
FROM customer_portfolios
WHERE portfolio_id = 954118
GROUP BY ticker
) cp
INNER JOIN price_history h
ON ( cp.ticker = h.ticker
AND cp.transaction_date BETWEEN h.start_date AND h.end_date )
or if the price history has a row per day (rather than the assumed range in the query above) then replace the last line with:
AND cp.transaction_date = h.price_date )

Answer 2

Perhaps, I'm missing something here but without any real sample data, this is the best I can come up with. Below are the table ddl's, inserts and query and an image of the results.
CREATE TABLE PRICE_HISTORY
( PRICE_DATE DATE,
TICKER VARCHAR2(20 BYTE),
OPEN_PRICE NUMBER,
CLOSE_PRICE NUMBER
)
CREATE TABLE PORTFOLIO_TABLE
( TICKER VARCHAR2(20 BYTE),
TICKER_DATE VARCHAR2(20 BYTE),
CUSTOMER VARCHAR2(20 BYTE)
)
Insert into PORTFOLIO_TABLE (TICKER,TICKER_DATE,CUSTOMER) values ('CYSL','1/16/2018','1');
Insert into PORTFOLIO_TABLE (TICKER,TICKER_DATE,CUSTOMER) values ('MCIG','04/1/2016','2');
Insert into PORTFOLIO_TABLE (TICKER,TICKER_DATE,CUSTOMER) values ('MSRT','09/13/2016','3');
Insert into PORTFOLIO_TABLE (TICKER,TICKER_DATE,CUSTOMER) values ('NTFU','01/16/2017','4');
Insert into PRICE_HISTORY (PRICE_DATE,TICKER,OPEN_PRICE,CLOSE_PRICE) values (to_date('27-MAR-2017 20:27:12','DD-MON-RRRR HH24:MI:SS'),'CYSL',1,2);
Insert into PRICE_HISTORY (PRICE_DATE,TICKER,OPEN_PRICE,CLOSE_PRICE) values (to_date('16-JUN-1997 20:27:33','DD-MON-RRRR HH24:MI:SS'),'MCIG',1,2);
Insert into PRICE_HISTORY (PRICE_DATE,TICKER,OPEN_PRICE,CLOSE_PRICE) values (to_date('31-MAY-2011 20:27:45','DD-MON-RRRR HH24:MI:SS'),'MSRT',5,8);
Insert into PRICE_HISTORY (PRICE_DATE,TICKER,OPEN_PRICE,CLOSE_PRICE) values (to_date('25-JAN-2021 20:27:55','DD-MON-RRRR HH24:MI:SS'),'NTFU',7,6);
WITH portfolio AS
( SELECT TICKER , TICKER_DATE, CUSTOMER FROM PORTFOLIO_TABLE
)
SELECT
CASE
WHEN PRICE_DATE > '01-JAN-17'
THEN CLOSE_PRICE
ELSE OPEN_PRICE
END AS AMOUNT,
PRICE_DATE,
P.TICKER,
OPEN_PRICE,
CLOSE_PRICE
FROM PRICE_HISTORY H,
PORTFOLIO P
WHERE H.TICKER = P.TICKER;

Answer 3

The ultimate goal of this query is to get a SUM of the customers portfolio, on his purchases.
This part is working perfectly!
SELECT m_ticker,
GREATEST(
DATE '2016-12-31',
MIN(transaction_date) KEEP (
DENSE_RANK FIRST
ORDER BY transaction_date
)
) AS transaction_date
FROM customer_portfolio_history
WHERE portfolio_id = 954118
GROUP BY m_ticker;
Gives me the data I need:
CYSL 1/16/2017
MCIG 12/31/2016
MSRT 12/31/2016
NTFU 1/16/2017
QNTM 12/31/2016
SIGWX 12/31/2016
TRMCX 12/31/2016
TRT2 12/31/2016
Now it gets trickier. With the results above, I need to go into the PRICE_HISTORY, and find the price which is on or closest to (earlier) that date.
So, if there is no entry for 12/31/2016 (maybe market was closed), then try 12/30, 12/29, etc. Same for 1/16/2017. If there is no entry, then try 1/15, then 1/14....
After, I can take the total # shares from the PORTFOLIO table for that customer / portfolio / ticker, and multiply it by the price I retrieve for the day found.....and there is the value.
Pretty crazy, I know.