USING NOT NULL

   This will gives the output based on the not null values in the specified column.

     Syntax:

         select * from <table_name> where <col> is not null;

     Ex:         

         SQL> select * from student where marks is not null;

         NO NAME            MARKS

         ---  -------           ---------

         1   Sudha             100

         2   Saketh            200

         1   Jagan             300

         2   Naren             400