I am trying to Select all records in the claims data where the “from\_date” field is before the “eff\_date” for the same “emp\_ssn”, same “pt\_ssn”, in the "patient data". 

```
SELECT *
FROM CLAIM 
   left join PATIENT on claim.pt_ssn = Patient.pt_ssn
WHERE (CLAIM.emp_ssn = Patient.emp_num AND Patient.pt_ssn=Claim.pt_ssn) 
  AND (CLAIM.FROM_DATE < Patient.eff_date);

```

This is giving me undesired results also with duplicates. 

I have tried left join, right join, inner join, and no join. I still cannot receive desired result. Any help would be appreciated.