Hi Akhil,
I was incomplete and partially incorrect on my answer.
If you export in CSV the data will be appended, so for NEW data it will not be a problem:
IMPORT - SAP HANA SQL and System Views Reference - SAP Library
For old that you can carrefully delete it previously. Example:
Table XPTO with PK (FIELD1, FIELD2)
DELETE FROM B.XPTO WHERE EXISTS (SELECT 1 FROM A.XPTO WHERE A.FIELD1=B.FIELD1 and A.FIELD2=B.FIELD2);
or within in
DELETE FROM B.XPTO WHERE (FIELD1,FIELD2) IN (SELECT FIELD1,FIELD2 FROM A.XPTO);
Regards, Fernando Da Rós