to_number function questions

On Tue, Sep 17, 2002 at 12:26:57PM -0700, Cindy wrote:

What does to_number do with a string like "123x78" ? Does
it try to convert the whole string? Does it stop at x, giving 123?
Does it drop x? Does it return some sort of failure?

test=# select to_number('123x78', '999x99');
to_number
-----------
12378

test=# select to_number('123x78', '999');
to_number
-----------
123

test=# select to_number('123x78', '999999');
to_number
-----------
12378

test=# select to_number('123xxx78', '999yyy99');
to_number
-----------
12378

Also, suppose that you give to_number 123, and the second parameter is
"999999" ? Do the extra 9's give any problem (you dn't always know
whether to_number will get 0-99999, so what do you give it in the
formatting string? If it has more 9's in the format string than are
digits in the number, will it pad it?

test=# select to_number('123', '99999999999999999999999');
to_number
-----------
123

Sorry for all the q's but the page
http://www.postgresql.org/idocs/index.php?functions-formatting.html
only lists things in tables and does not discuss the sorts of questions
or oddball inputs/exceptions I ask about.

The docs expect that user knows 'psql' and knows method how test wanted
questions before post it to PG lists :-) The patches with better docs are
wanted of course.

Karel

--
Karel Zak <zakkr@zf.jcu.cz>
http://home.zf.jcu.cz/~zakkr/

C, PostgreSQL, PHP, WWW, http://docs.linux.cz, http://mape.jcu.cz