Select works but when I do update I get error
UPDATE DIM t1
SET CURR_FLG=
SELECT
CASE WHEN A.RN=1 THEN 'Y' ELSE 'N' END as CURR_FLG
FROM
(
SELECT
EMPLID,
EMPL_RCD,
EFFDT,
LST_ASGN_START_DT,
EMPL_STATUS,
ROW_NUMBER() OVER (PARTITION BY EMPLID,EMPL_RCD ORDER BY EFFDT DESC) AS RN
FROM DIM
WHERE EFFDT<=SYSDATE)A
WHERE t1.JOB_SID=A.JOB_SID
When I see an update like this, I think of MERGE:
http://docs.oracle.com/cd/E11882_01/server.112/e41084/statements_9016.htm#SQLRF01606
There are many examples out there.