SELECT Statement Criteria Help

Question

Hello Friends,
LM_SUPERVISOR_ID and SUPERVISOR_ID are character fields in the database .
I am getting the rows even when SUPERVISOR_ID and LM_SUPERVISOR_ID equal When i use not equl in criteria . I trien using to_char () function . what else could be wrong in SQL ?
SELECT DISTINCT A.SUPERVISOR_ID
,A.EMPLID ,A.EFFDT
FROM PS_JOB@h88vatst A
, PS_LM_PERSON B
, PS_LM_PERSON_JOB C
WHERE A.EMPLID = B.LM_HR_EMPLID
AND C.LM_PERSON_ID = B.LM_PERSON_ID
AND A.SUPERVISOR_ID <> ' '
AND C.LM_SUPERVISOR_ID <> A.SUPERVISOR_ID
regards,
Karu

Answer 1

Karu,
The output that you are getting is due to cartesian product.
Maybe following is what you are looking for:
SQL> ed
Wrote file afiedt.buf
  1  SELECT DISTINCT A.SUPVID
  2  ,A.EMPLID
  3  FROM PS_JOB A
  4  , LM_PERSON B
  5  , PS_LM_PERSON_JOB C
  6  WHERE C.PERSON_ID = B.PERSONID
  7  AND A.SUPVID <> ' '
  8* AND (A.EMPLID, A.SUPVID) not in (select emplid, SUPVID from PS_LM_PERSON_JOB)
SQL> /
SUPVID     EMPLID
000025     000008However, you need to consider what Kamal has asked about nullibility of EMPLID and SUPVID columns and how do you want to handle them.
Not sure (and don't have enough information about your application), but seemed something fishy about your design. Hope you have ensured these 3 tables are related to each other (i.e. referrential integrity and one-to-many, many-to-many relationships etc) in a way that satisfies your business requirement completely.