diff --git a/administrator/components/com_admin/sql/updates/mysql/4.0.0-2019-07-27.sql b/administrator/components/com_admin/sql/updates/mysql/4.0.0-2019-07-27.sql
index 9e0eed4c16171..41be7ae3c2fe3 100644
--- a/administrator/components/com_admin/sql/updates/mysql/4.0.0-2019-07-27.sql
+++ b/administrator/components/com_admin/sql/updates/mysql/4.0.0-2019-07-27.sql
@@ -10,14 +10,14 @@ ALTER TABLE `#__tags` MODIFY COLUMN `checked_out_time` DATETIME NULL DEFAULT NUL
 ALTER TABLE `#__ucm_content` MODIFY COLUMN `core_checked_out_time` DATETIME NULL DEFAULT NULL;
 ALTER TABLE `#__user_notes` MODIFY COLUMN `checked_out_time` DATETIME NULL DEFAULT NULL;
 
-UPDATE `#__banner_clients` SET `checked_out_time` = null WHERE `checked_out_time` = '0000-00-00 00:00:00';
-UPDATE `#__categories` SET `checked_out_time` = null WHERE `checked_out_time` = '0000-00-00 00:00:00';
-UPDATE `#__content` SET `checked_out_time` = null WHERE `checked_out_time` = '0000-00-00 00:00:00';
-UPDATE `#__extensions` SET `checked_out_time` = null WHERE `checked_out_time` = '0000-00-00 00:00:00';
-UPDATE `#__fields` SET `checked_out_time` = null WHERE `checked_out_time` = '0000-00-00 00:00:00';
-UPDATE `#__fields_groups` SET `checked_out_time` = null WHERE `checked_out_time` = '0000-00-00 00:00:00';
-UPDATE `#__finder_filters` SET `checked_out_time` = null WHERE `checked_out_time` = '0000-00-00 00:00:00';
-UPDATE `#__menu` SET `checked_out_time` = null WHERE `checked_out_time` = '0000-00-00 00:00:00';
-UPDATE `#__tags` SET `checked_out_time` = null WHERE `checked_out_time` = '0000-00-00 00:00:00';
-UPDATE `#__ucm_content` SET `core_checked_out_time` = null WHERE `core_checked_out_time` = '0000-00-00 00:00:00';
-UPDATE `#__user_notes` SET `checked_out_time` = null WHERE `checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__banner_clients` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__categories` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__content` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__extensions` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__fields` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__fields_groups` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__finder_filters` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__menu` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__tags` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__ucm_content` SET `core_checked_out_time` = NULL WHERE `core_checked_out_time` = '0000-00-00 00:00:00';
+UPDATE `#__user_notes` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
diff --git a/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2019-07-27.sql b/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2019-07-27.sql
index b5476f2d1f766..3e3c486222419 100644
--- a/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2019-07-27.sql
+++ b/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2019-07-27.sql
@@ -16,19 +16,19 @@ ALTER TABLE "#__menu" ALTER COLUMN "checked_out_time" DROP DEFAULT;
 ALTER TABLE "#__menu" ALTER COLUMN "checked_out_time" DROP NOT NULL;
 ALTER TABLE "#__tags" ALTER COLUMN "checked_out_time" DROP DEFAULT;
 ALTER TABLE "#__tags" ALTER COLUMN "checked_out_time" DROP NOT NULL;
-ALTER TABLE "#__ucm_content" ALTER COLUMN "checked_out_time" DROP DEFAULT;
-ALTER TABLE "#__ucm_content" ALTER COLUMN "checked_out_time" DROP NOT NULL;
+ALTER TABLE "#__ucm_content" ALTER COLUMN "core_checked_out_time" DROP DEFAULT;
+ALTER TABLE "#__ucm_content" ALTER COLUMN "core_checked_out_time" DROP NOT NULL;
 ALTER TABLE "#__user_notes" ALTER COLUMN "checked_out_time" DROP DEFAULT;
 ALTER TABLE "#__user_notes" ALTER COLUMN "checked_out_time" DROP NOT NULL;
 
-UPDATE "#__banner_clients" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
-UPDATE "#__categories" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
-UPDATE "#__content" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
-UPDATE "#__extensions" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
-UPDATE "#__fields" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
-UPDATE "#__fields_groups" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
-UPDATE "#__finder_filters" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
-UPDATE "#__menu" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
-UPDATE "#__tags" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
-UPDATE "#__ucm_content" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
-UPDATE "#__user_notes" SET "checked_out_time" = null WHERE "checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__banner_clients" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__categories" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__content" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__extensions" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__fields" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__fields_groups" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__finder_filters" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__menu" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__tags" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__ucm_content" SET "core_checked_out_time" = NULL WHERE "core_checked_out_time" = '1970-01-01 00:00:00';
+UPDATE "#__user_notes" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
diff --git a/administrator/components/com_checkin/Model/CheckinModel.php b/administrator/components/com_checkin/Model/CheckinModel.php
index 790faa44b8bce..e2e8faee32fb1 100644
--- a/administrator/components/com_checkin/Model/CheckinModel.php
+++ b/administrator/components/com_checkin/Model/CheckinModel.php
@@ -110,7 +110,7 @@ public function checkin($ids = array())
 			$query = $db->getQuery(true)
 				->update($db->quoteName($tn))
 				->set($db->quoteName('checked_out') . ' = DEFAULT')
-				->set($db->quoteName('checked_out_time') . ' = null')
+				->set($db->quoteName('checked_out_time') . ' = NULL')
 				->where($db->quoteName('checked_out') . ' > 0');
 
 			$db->setQuery($query);