diff --git a/infolog/inc/class.soinfolog.inc.php b/infolog/inc/class.soinfolog.inc.php
index de1bd7f97d..388dc4af41 100644
--- a/infolog/inc/class.soinfolog.inc.php
+++ b/infolog/inc/class.soinfolog.inc.php
@@ -478,6 +478,9 @@ class soinfolog 				// DB-Layer
 				$to_write[$key] = $this->data[$key] = $val;   // update internal data
 			}
 		}
+		// writing no price as SQL NULL (required by postgres)
+		if ($to_write['info_price'] === '') $to_write['info_price'] = NULL;
+
 		if (($this->data['info_id'] = $info_id))
 		{
 			$where = array('info_id' => $info_id);