Re: partial JOIN (was: ID column naming convention)

On 10/25/15 2:30 AM, Rafal Pietrak wrote:
> So personally, I don't see a star in a select list so harmfull, quite
> the oposit.

Using * outside the database is generally very dangerous. Using it
*inside* the database can be very useful, because frequently it's
exactly what you want (give me all the columns, dammit!). In particular,
I find it useful in views where I want the original data, along with
some calculated or other values. For example,

SELECT nspname, c.oid, * FROM pg_class c LEFT JOIN pg_namespace ON...

But there's also times I've wanted a way to manipulate what * would
normally do. In particular, *_except_for(field_list), and *_replace(
regexp_replace to run on each field name). If those existed (and maybe a
way to combine them), it wouldn't be terribly hard for you do handle
your sled query with something like:

SELECT s.*, l.*( s/.*/left_%/ ), r.*( s/.*/right_& )
   FROM sled s JOIN runner l ON ... JOIN runner r ON ...
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com