SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6 pl2): Invalid SQL: UPDATE bb1_guthaben_bank SET akt_jahr='2021', crashtag='307', boersencrash='0',boersencrashdate = '', boersencrashaktienwert='', boersencrashprozent='',boersencrashaktienwertneu='' WHERE bankid='1'
mysql error: Incorrect integer value: '' for column `admin_galaxy_1`.`bb1_guthaben_bank`.`boersencrashaktienwert` at row 1
mysql error number: 1366
mysql version: 10.2.38-MariaDB
php version: 5.3.29
Date: 14.05.2021 @ 05:24
Script: /wbb2/login.php?sid=d9f9ce727af46ac4f390af7d37547630
Referer: