There are some problems with running Drupal on php 5.3. There are five kinds of solutions:

1. Downgrade to php 5.2.6 (not possible in many situations)
2. modify Drupal to change the error level reporting
3. find the latest patches to fix the problems
4. hack Drupal core or contrib yourself to fix the errors (Drupal 6 is already compliant, but not D5)
5. put a timezone in your php.ini to get rid of timezone errors

Drupal 6

2. Modify Drupal's error reporting --already done for Drupal 6

3. Find patches

This are probably not of general interest, just some example queries from a particular database that I wanted to save here as snippets.

--view all category titles from node: n & d, category node: c
$sql="SELECT n.nid, c.title AS cname, d.field_catcache_value AS cat FROM node AS n"
. " JOIN content_type_document AS d ON d.nid=n.nid AND d.vid=n.vid"
. " JOIN node AS c ON c.nid=d.field_category_nid"
. " WHERE n.type = 'document'";

--get the body of the category definition c from a given node n & d
SELECT n.nid, c.title, r.body AS cname FROM node AS n

Single node output: Sony use Drupal

Get many items using an object

pre{border:none;background-color:#f4f3d7;padding:1em;-moz-border-radius:10px}

<?php
exec("mysqldump -uDBUSER -pPASSWORD DBNAME > DBNAME.sql");
exec("tar -czvf BACKUP.tar.gz .");
print "Done";