diff --git a/api/src/Db/Pdo.php b/api/src/Db/Pdo.php
index 6c3f40776c..2b596e1945 100644
--- a/api/src/Db/Pdo.php
+++ b/api/src/Db/Pdo.php
@@ -104,6 +104,11 @@ class Pdo
 		{
 			case 'mysql':
 				$dsn .= ';charset=utf8';
+				// switch off MySQL 5.7+ ONLY_FULL_GROUP_BY sql_mode
+				if ($egw_db->ServerInfo['version'] >= 5.7 && $egw_db->ServerInfo['version'] < 10.0)
+				{
+					$query = "SET SESSION sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY',''))";
+				}
 				break;
 			case 'pgsql':
 				$query = "SET NAMES 'utf-8'";