Re: CAST from VARCHAR to INT
От | Roberto Mello |
---|---|
Тема | Re: CAST from VARCHAR to INT |
Дата | |
Msg-id | 20030124190356.GC20178@cc.usu.edu обсуждение исходный текст |
Ответ на | Re: CAST from VARCHAR to INT (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-sql |
On Fri, Jan 24, 2003 at 10:42:29AM -0500, Tom Lane wrote: > daq <daq@ugyvitelszolgaltato.hu> writes: > > Make your life easier! :) You must write a function like > > this: > > > create function "int4"(character varying) returns int4 as ' > > DECLARE > > input alias for $1; > > BEGIN > > return (input::text::int4); > > END; > > ' language 'plpgsql'; > > > When you try the cast varchar_field::integer or varchar_field::int4 Postgres call > > the function named int4 and takes varchar type parameter. > > Note that as of 7.3 you need to issue a CREATE CAST command; the name of > the function is not what drives this anymore. (Though following the old > naming convention that function name == return type still seems like a > good idea.) Wow, I didn't even know of either of these features. Sounds useful. -Roberto -- +----| Roberto Mello - http://www.brasileiro.net/ |------+ + Computer Science Graduate Student, Utah State University + + USU Free Software & GNU/Linux Club - http://fslc.usu.edu/ + Friends encourage friends to use Win(e)dows - under Linux!
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