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Re: a row disapearing

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Rafal Pietrak wrote:
> Hi All,
> 
> This is ambarasing, but I've just noticed the following (which looks
> inconsistant to inexperienced eye). Having a table:
> 
> 	test=> CREATE TABLE xxx (id int, info text);
> 
> With some rows in it, I try:
> 
> 	test=> SELECT count(1) from xxx where id=1;
> 	 count 
> 	-------
> 	     0
> 	(1 row)
> 
> This is correct (meaning, I expected that). But when I try to fetch the
> actual selector used in the query as well, I get no rows instead.
> 
> 	test=> SELECT count(1),id from xxx where id=1 group by id;
> 	 count | id 
> 	-------+----
> 	(0 rows)
> 
> Is this a feature, or a bug? And in fact, is there a construct to get
> both the count() and its selectors *in*case*, when the count is ZERO?
> 
> All the above in postgres 8.1.

It is supposed to work that way.  In the first query, we have to return
a row to show you the count, while in the second query, there is no 'id'
value to show you, so we return nothing (nothing to GROUP BY).

-- 
  Bruce Momjian   http://candle.pha.pa.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +


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