problem to compare a date-field with a string

[krueson]

Server : Informix Dynamic Server Version 7.31.UC7X9 on AIX 4.33
Client : Linux 2.4.19 ( Based on Slackware ) with Apache + PHP 4.2.3 + INFORMIX-Client SDK Version 2.60.UC1

I'm trying to compare a date-column with a string to update values in a table

$query="select datefield from bla";
ifx_query($query, $conn_id);

the results are:
01.10.2001
01.10.2001
01.10.2001
01.06.2001
...

$query="update bla set fieldone=NULL where datefield='01.10.2000'"; // Date e.q. 10/01/2000
ifx_query($query, $conn_id);

Warning: Prepare fails (E [SQLSTATE=42 000 SQLCODE=-201])
...This general error message indicates mistakes in the form of an SQL statement...

The same query on dbaccess (server aix4.33) works fine !

environment on aix 4.33
DB_LOCALE=de_de.8859-1
CLIENT_LOCALE=de_de.8859-1
DBMONEY=.

environment on linux/php > phpinfo()
INFORMIXTAGE 180
DB_LOCALE de_de.8859-1
CLIENT_LOCALE de_de.8859-1
DBDATE DMY4.

Any ideas? Every help is great !
Thanks
krueson

[Lars_Berg]

Found this in an old (7.1) manual.

$query="update bla set fieldone=NULL where datefield= datetime(2000-01-10) year to day";