Re: [SQL] problem with select

Tom Lane wrote:

> Holm Tiffe <holm@freibergnet.de> writes:
> > What I try to find is a solution for a search in this table like this:
> 
> > select distinct code,category from products where code ~* 'abc' or
> > category ~* 'abc' or manufacturer ~* 'abc' or description ~* 'abc'
> > or comment ~* 'abc' order by code;
> 
> > So far so good, but I have the problem that I have the value 'abc'
> > only one times !
> 
> How about
> 
> select distinct code,category from products where
> (code || category || manufacturer || ...) ~* 'abc';
> 
> Actually you'd probably want to also concatenate some separator markers,
> maybe (code || '|' || category || ...), so that you didn't get bogus
> matches across fields, like where code ends in 'a' and category starts
> with 'bc'.
> 
> Note that this select will be a bit of a memory hog because
> text-slinging is very wasteful of space in 6.5 (the intermediate results
> from the concatenate operators don't get freed till end of transaction).
> So it might not be workable if you have a large database.  I hope to see
> that fixed for 6.6 or 6.7.
> 
>             regards, tom lane

Hm, clever.

It is almost working, my database isn't that big that memory becomes a
problem; the machine has 512MB.

But why is nothing found if one value of a column contains NULL ?

select distinct code,category from products where (code || '|' || category|| '|' || comment || '|' || description ||
'|'|| desc_de) ~* 'kde'; code|category
 
------+--------
06-001|KDE     
(1 row)

shop=> update products set comment = Null where code ='06-001';
UPDATE 1
shop=> select (comment || '|' || code) from products where code ~* '06-001';
?column?
--------       
(1 row)

Holm
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