SQL-DATABASE ERROR

Database error in pd Script: Invalid SQL: Insert Into pd_rechnung (sessionid, zeit, art) Values ('ivaml8tbs2ealga8b7lfkholo1', 1695993303, 2)
mysql error: Field 'iduser' doesn't have a default value
mysql error number: 1364
Date: 29.09.2023 @ 15:15
Script: /rechnung_neu.php?step=2&art=2&phpMyAdmin=kSdVEcrW9JgLk8afnGhkZl7xHhe
Referer: