Oracle - how to update a unique row based on MAX effective date which is part of the unique index - oracle

Question

Oracle - Say you have a table that has a unique key on name, ssn and effective date. The effective date makes it unique. What is the best way to update a current indicator to show inactive for the rows with dates less than the max effective date? I can't really wrap my head around it since there are multiple rows with the same name and ssn combinations. I haven't been able to find this scenario on here for Oracle and I'm having developer's block. Thanks.

Answer 1

"All name/ssn having a max effective date earlier than this time yesterday:"
SELECT name, ssn
FROM t
GROUP BY name, ssn
HAVING MAX(eff_date) < SYSDATE - 1
Oracle supports multi column in, so
UPDATE t
SET current_indicator = 'inactive'
WHERE (name,ssn,eff_date) IN (
SELECT name, ssn, max(eff_date)
FROM t
GROUP BY name, ssn
HAVING MAX(eff_date) < SYSDATE - 1
)

Answer 2

Use a MERGE statement using an analytic function to identify the rows to update and then merge on the ROWID pseudo-column so that Oracle can efficiently identify the rows to update (without having to perform an expensive self-join by comparing the values):
MERGE INTO table_name dst
USING (
SELECT rid,
max_eff_date
FROM (
SELECT ROWID AS rid,
effective_date,
status,
MAX( effective_date ) OVER ( PARTITION BY name, ssn ) AS max_eff_date
FROM table_name
)
WHERE ( effective_date < max_eff_date AND status <> 'inactive' )
OR ( effective_date = max_eff_date AND status <> 'active' )
) src
ON ( dst.ROWID = src.rid )
WHEN MATCHED THEN
UPDATE
SET status = CASE
WHEN src.max_eff_date = dst.effective_date
THEN 'active'
ELSE 'inactive'
END;
So, for some sample data:
CREATE TABLE table_name ( name, ssn, effective_date, status ) AS
SELECT 'aaa', 1, DATE '2020-01-01', 'inactive' FROM DUAL UNION ALL
SELECT 'aaa', 1, DATE '2020-01-02', 'inactive' FROM DUAL UNION ALL
SELECT 'aaa', 1, DATE '2020-01-03', 'inactive' FROM DUAL UNION ALL
SELECT 'bbb', 2, DATE '2020-01-01', 'active' FROM DUAL UNION ALL
SELECT 'bbb', 2, DATE '2020-01-02', 'inactive' FROM DUAL UNION ALL
SELECT 'bbb', 3, DATE '2020-01-01', 'inactive' FROM DUAL UNION ALL
SELECT 'bbb', 3, DATE '2020-01-03', 'active' FROM DUAL;
The query only updates the 3 rows that need changing and:
SELECT *
FROM table_name;
Outputs:
NAME | SSN | EFFECTIVE_DATE | STATUS
:--- | --: | :------------- | :-------
aaa | 1 | 01-JAN-20 | inactive
aaa | 1 | 02-JAN-20 | inactive
aaa | 1 | 03-JAN-20 | active
bbb | 2 | 01-JAN-20 | inactive
bbb | 2 | 02-JAN-20 | active
bbb | 3 | 01-JAN-20 | inactive
bbb | 3 | 03-JAN-20 | active
db<>fiddle here