Oracle DB server notes

Oracle Error:
Warning: ocifetch(): OCIFetch: ORA-24374: define not done before fetch or execute and fetch in /home/martin/dev/www/inc/ora_funct.php on line 15

Reason and solution:
sometimes wrong syntax but mostly missing access rights to accessed table. You can solve this problem by granting sufficient rights to the user which is accessing the table.

Oracle sql date comparison:
SELECT column
FROM table
WHERE start_date <= TO_DATE('20080401', 'yyyy-mm-dd');