What is the difference between rowid and rownum
ROWID is a pseudo column and is the unique address of a row.
Select rowid From dual Where user='SYSTEM';
Select user From dual Where rowid='AAAAB0AABAAAAOhAAA';
ROWNUM represents the number of the row after it has been retrieved from the the database after a query has been made.
Select rownum, name, email
Where rownum > 500
Order By name;