Re: don't know how to get SELECT

From: Darren Ferguson <darren(at)crystalballinc(dot)com>
To: Uros Gruber <uros(at)sir-mag(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: don't know how to get SELECT
Date: 2002-05-13 17:51:17
Message-ID: Pine.LNX.4.10.10205131348470.8555-100000@thread.crystalballinc.com
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Use the EXECUTE command.

This allows the execution of dynamic queries

EXECUTE ''UPDATE ''||table||'' SET id = ''||id||''WHERE something =
something'';

This is just an example but it shows how to execute dynamic queries

HTH

Darren Ferguson

On Mon, 13 May 2002, Uros Gruber wrote:

> Hi!
>
> i have some problems with plpgsql. Here is my function
>
>
> create or replace function rm_cat(varchar,int) returns boolean as '
> declare
> table alias for $1;
> id alias for $2;
> data RECORD;
> begin
> ******************************************************************
> SELECT INTO data lft,rgt FROM d_categories WHERE id_category=id;
> ******************************************************************
> IF NOT FOUND THEN
> RAISE EXCEPTION ''id % does not exist'',id;
> return 0;
> end if;
>
> -- deleting the leftmost node does not lower lft for all
> execute ''update '' || quote_ident(table) || '' set level=level-1 where lft > '' || data.lft || ''and rgt < '' || data.rgt || '';'';
> execute ''update '' || quote_ident(table) || '' set lft=lft-1 where lft >= '' || data.lft || '';'';
> execute ''update '' || quote_ident(table) || '' set lft=lft-1 where lft >= '' || data.rgt || '';'';
> execute ''update '' || quote_ident(table) || '' set rgt=rgt-1 where rgt >= '' || data.lft || '';'';
> execute ''update '' || quote_ident(table) || '' set rgt=rgt-1 where rgt >= '' || data.rgt || '';'';
> execute ''delete from '' || quote_ident(table) || '' where id_category = '' || id || '';'';
> return 1;
> end;
> 'language 'plpgsql';
>
>
> My problems is in line wraped with ***. What i want is that
> SELECT have to be dinamyc because i want with an argument to
> saj for what table do this select. I tried many ways and i
> think i don't understand something. Can somebody help me
> solve this.
>
>
>
> --
> bye,
> Uros mailto:uros(dot)gruber(at)sir-mag(dot)com
>
>
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