i read comment table in qlikview reference manual book.but i do not understand comment table .how to use comment table in script .
please tell me out.and send to me some examples (or) videos of comment table.
You just create some meta data, i.e. a description / comment on your table (you'll see this comment in table viewer when hovering over with the mouse).
Example from the HELP:
comment table Main with ‘Main fact table’;
Retrieving data ...