select "Rental".*,ora_rowscn from "Rental"

SELECT "Rental".*, ORA_ROWSCN FROM "Rental"
  inner join "UserBranch" on  "UserBranch"."fkBranchId" = "Rental"."fkBranchId"
  WHERE "Rental"."IsDeleted"='N' ;

ORA-00904: "ORA_ROWSCN": invalid identifier

select ora_rowscn,"myTable"."pkRentalId" from (select "Rental"."pkRentalId"  from "Rental"  inner join "UserBranch" on  "UserBranch"."fkBranchId" = "Rental"."fkBranchId"
  WHERE "Rental"."IsDeleted"='N' ) "myTable"