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From: Arno Welzel <usenet@arnowelzel.de>
Newsgroups: comp.lang.php
Subject: Re: Fast/Easy way to extract a column from multi-dimensional array?
Date: Sat, 28 Jan 2012 09:49:08 +0100
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John Drako, 2012-01-27 21:08:

> I'm looking for a way to get all the values from the column of a two 
> dimensional array.
> 
> For example, I have a query on a mysql database that returns 10 rows 
> from the database, I would like to quickly (read low cpu load) extract 
> all the IDs from all the rows returned to reuse in another query.
> 
> So let's say I use:
> 
> $arr = mysqli_fetch_all($result, MYSQLI_ASSOC);
> 
> and $arr looks like:
> 
> RecordID, name, last name, title
> RecordID, name, last name, title
> RecordID, name, last name, title
> RecordID, name, last name, title
> RecordID, name, last name, title
> RecordID, name, last name, title
> etc...
> 
> I need to get all the 'RecordID' from the results to reuse in other 
> queries.
[...]
> The site is very busy and CPU cycles count. I'm trying to avoid left 
> joining three gigantic tables.

You always query *all* records with every request?

And do you already use some kind of byte code cache (XCache etc.)? This
also helps a lot to reduce the CPU load and the scripts can be executed
3-4 times faster, since the interpretation will only be done once and
further requests get served by the cached byte code.


-- 
Arno Welzel
http://arnowelzel.de
http://de-rec-fahrrad.de