diff --git a/Resources/migrations/VersionAuthserverExternalAccount20171020220239.php b/Resources/migrations/VersionAuthserverExternalAccount20171020220239.php
index 2d7afe9..4e2a245 100644
--- a/Resources/migrations/VersionAuthserverExternalAccount20171020220239.php
+++ b/Resources/migrations/VersionAuthserverExternalAccount20171020220239.php
@@ -32,7 +32,8 @@ class VersionAuthserverExternalAccount20171020220239 extends AbstractMigration
         $duplicateIds = array_map(function ($row) {
             return $row['id'];
         }, $duplicates);
-        $this->connection->executeUpdate('DELETE FROM vierbergenlars_external_account_external_user WHERE id IN(' . implode(',', $duplicateIds) . ')');
+        if (count($duplicateIds) > 0)
+            $this->connection->executeUpdate('DELETE FROM vierbergenlars_external_account_external_user WHERE id IN(' . implode(',', $duplicateIds) . ')');
     }
 
     public function down(Schema $schema)