Oracle SQL- Flag records based on record's date vs history - sql

Question

This is my 1st post on the forum. Usually I was able to find what I needed - but to tell the truth - I am not really sure how to ask a correct question to the issue. Therefore, please accept my apologies if there already is an answer on the forum and I missed it.
I am running the following code in an Oracle database via Benthic Software:
SELECT
T1."REGION"
, T1."COUNTRY"
, T1."IDNum"
, T1."CUSTOMER"
, T1."BUSSINESS"
, T3."FISCALYEARMONTH"
, T3."FISCALYEAR"
, SUM(T4."VALUE")
,"HISTORICAL_PURCHASE_FLAG"
FROM
"DATABASE"."SALES" T4
, "DATABASE"."CUSTOMER" T1
, "DATABASE"."PRODUCT" T2
, "DATABASE"."TIME" T3
WHERE
T4."CUSTOMERID" = T1."CUSTOMERID"
AND T4."PRODUCTID" = T2."PRODUCTID"
AND T4."DATEID" = T3."DATEID"
AND T3."FISCALYEAR" IN ('2016')
AND T1."COUNTRY" IN ('ENGLAND', 'France')
GROUP BY
T1."REGION"
, T1."COUNTRY"
, T1."IDNum"
, T1."CUSTOMER"
, T1."BUSSINESS"
, T3."FISCALYEARMONTH"
, T3."FISCALYEAR"
;
This query provides me with information on transactions. As you can see above, I would like to add a column named "HISTORICAL_PURCHASE_FLAG".
I would like the query to take CUSTOMER and FISCALYEARMONTH. Then, I would like to check if there are any transactions registered for the CUSTOMER, up to 2 years in the past.
So lets say I get the following result:
LineNum REGION COUNTRY IDNum CUSTOMER BUSSINESS FISCALYEARMONTH FISCALYEAR VALUE HISTORICAL_PURCHASE_FLAG
1 Europe ENGLAND 255 Abraxo Cleaner Co. Chemicals 201605 2016 34,567.00
2 Europe FRANCE 123 Metal Trade Heavy 201602 2016 12,500.00
3 Europe ENGLAND 255 Abraxo Cleaner Co. Chemicals 201601 2016 8,400.00
LineNum 1 shows transaction for Abraxo Cleaner Co. registered on 201605. And LineNum 3 is also for Abraxo Cleaner Co. but registered on 201601. What I would need the query to do, is to flag LineNum 1 as 'Existing'. Because there was a previous transaction registered.
On the other hand, LineNum 3 was the first time transactions was registered for Abraxo Cleaner Co. so the line would be flagged as 'New'.
To sum up, I would like for each row of data to be treated individually. And to check if there are any previous records of data for CUSTOMER & FISCALYEARMONTH - 24 months.
Thank you in advance for the help.

Answer 1

You can use LAG function:
SELECT
"REGION"
, "COUNTRY"
, "IDNum"
, "CUSTOMER"
, "BUSSINESS"
, "FISCALYEARMONTH"
, "FISCALYEAR"
, SUM("VALUE")
, MAX(CASE WHEN to_date(prev_fym,'YYYYMM') >= ADD_MONTHS (to_date("FISCALYEARMONTH",'YYYYMM'), -24) THEN 'Existing'
ELSE NULL END) "HISTORICAL_PURCHASE_FLAG"
FROM
(
SELECT
T1."REGION"
, T1."COUNTRY"
, T1."IDNum"
, T1."CUSTOMER"
, T1."BUSSINESS"
, T3."FISCALYEARMONTH"
, T3."FISCALYEAR"
, T4."VALUE"
, LAG ("FISCALYEARMONTH", 1) OVER (PARTITION BY T1."IDNum" ORDER BY T3."FISCALYEARMONTH" DESC) prev_fym
FROM
"DATABASE"."SALES" T4
, "DATABASE"."CUSTOMER" T1
, "DATABASE"."PRODUCT" T2
, "DATABASE"."TIME" T3
WHERE
T4."CUSTOMERID" = T1."CUSTOMERID"
AND T4."PRODUCTID" = T2."PRODUCTID"
AND T4."DATEID" = T3."DATEID"
AND T1."COUNTRY" IN ('ENGLAND', 'France')
AND T3."FISCALYEAR" IN ('2014','2015','2016')
)
WHERE "FISCALYEAR" IN ('2016')
GROUP BY
"REGION"
, "COUNTRY"
, "IDNum"
, "CUSTOMER"
, "BUSSINESS"
, "FISCALYEARMONTH"
, "FISCALYEAR"
;

Answer 2

Using a simplified "input" table... You can use the LAG() analytic function and a comparison condition to populate your last column. I assume your fiscalyearmonth is a number - if it is a character field, wrap fiscalyearmonth within TO_NUMBER(). (It would be much better if in fact you stored these as true Oracle dates, perhaps date 2016-06-01 instead of 201606, but I worked with what you have currently... and took advantage that in numeric format, "24 months ago" simply means "subtract 200").
with inputs (linenum, idnum, fiscalyearmonth) as (
select 1, 255, 201605 from dual union all
select 2, 123, 201602 from dual union all
select 3, 255, 201601 from dual union all
select 4, 255, 201210 from dual
)
select linenum, idnum, fiscalyearmonth,
case when fiscalyearmonth
- lag(fiscalyearmonth)
over (partition by idnum order by fiscalyearmonth) < 200
then 'Existing' else 'New' end as flag
from inputs
order by linenum;
LINENUM IDNUM FISCALYEARMONTH FLAG
---------- ---------- --------------- --------
1 255 201605 Existing
2 123 201602 New
3 255 201601 New
4 255 201210 New

Answer 3

Another solution might be to outer Join "DATABASE"."SALES" T4 a second time as T5, wilter the fiscal year via WHERE to < t4.FiscalYear-2. If the Column is NULL, the record is new, if the outer join results in a value, the record is historic.

Answer 4

You can achieve using row_number() function as below... modify as per your need...I assumed 2 years (means previous 24 months from sysdate ).
You can run the sub-queries separately to check how its working.
Select
"REGION"
,"COUNTRY"
,"IDNum"
,"CUSTOMER"
,"BUSSINESS"
,"FISCALYEARMONTH"
,"FISCALYEAR"
,"VALUE"
, ( case when ( TXNNO = 1 or TOTAL_TXN_LAST24MTH = 0 ) then 'New' else 'Existing' end ) as "HISTORICAL_PURCHASE_FLAG" -- if no txn in last 24 month or its first txn then 'new' else 'existing'
from
(
select
SubQry."REGION"
, SubQry."COUNTRY"
, SubQry."IDNum"
, SubQry."CUSTOMER"
, SubQry."BUSSINESS"
, SubQry."FISCALYEARMONTH"
, SUBQRY."FISCALYEAR"
, SUBQRY."VALUE"
, ROW_NUMBER() over (partition by SUBQRY."REGION",SUBQRY."COUNTRY",SUBQRY."IDNum",SUBQRY."CUSTOMER",SUBQRY."BUSSINESS" order by SUBQRY."FISCALYEARMONTH") as TXNNO,
, SUM(case when (TO_NUMBER(TO_CHAR(sysdate,'YYYYMM')) - SUBQRY."FISCALYEARMONTH") < 24 then 1 else 0 end) as TOTAL_TXN_LAST24MTH
From
(
SELECT
T1."REGION"
, T1."COUNTRY"
, T1."IDNum"
, T1."CUSTOMER"
, T1."BUSSINESS"
, T3."FISCALYEARMONTH"
, T3."FISCALYEAR"
, SUM(T4."VALUE") as VALUE
FROM
"DATABASE"."SALES" T4
, "DATABASE"."CUSTOMER" T1
, "DATABASE"."PRODUCT" T2
, "DATABASE"."TIME" T3
WHERE
T4."CUSTOMERID" = T1."CUSTOMERID"
AND T4."PRODUCTID" = T2."PRODUCTID"
AND T4."DATEID" = T3."DATEID"
AND T3."FISCALYEAR" IN ('2016')
AND T1."COUNTRY" IN ('ENGLAND', 'France')
GROUP BY
T1."REGION"
, T1."COUNTRY"
, T1."IDNum"
, T1."CUSTOMER"
, T1."BUSSINESS"
, T3."FISCALYEARMONTH"
, T3."FISCALYEAR"
) SUBQRY
);