Plan for the query is

Code:
OPERATION                      OPTIONS         OBJECT_NAME
------------------------------ --------------- -------------------------
SELECT STATEMENT
MERGE JOIN
SORT                           JOIN
VIEW
SORT                           GROUP BY
TABLE ACCESS                   FULL            PI_SLOC_USER_INV
SORT                           JOIN
VIEW
SORT                           GROUP BY
TABLE ACCESS                   FULL            PI_SLOC_SAP_INV