Merge branch 'bug/376-mysql-5.7-order_by' into 2.8

1 files changed, 13 insertions, 0 deletions

diff --git a/include/dblayer/functions_mysqli.inc.php b/include/dblayer/functions_mysqli.inc.php
index 5b40cfe5b..21adbeabe 100644
--- a/include/dblayer/functions_mysqli.inc.php
+++ b/include/dblayer/functions_mysqli.inc.php
@@ -73,6 +73,19 @@ function pwg_db_connect($host, $user, $password, $database)
   {
     throw new Exception('Connection to server succeed, but it was impossible to connect to database');
   }
+
+  // MySQL 5.7 default settings forbid to select a colum that is not in the
+  // group by. We've used that in Piwigo, for years. As an immediate solution
+  // we can remove this constraint in the current MySQL session.
+  list($sql_mode_current) = pwg_db_fetch_row(pwg_query('SELECT @@SESSION.sql_mode'));
+
+  // remove ONLY_FULL_GROUP_BY from the list
+  $sql_mode_altered = implode(',', array_diff(explode(',', $sql_mode_current), array('ONLY_FULL_GROUP_BY')));
+
+  if ($sql_mode_altered != $sql_mode_current)
+  {
+    pwg_query("SET SESSION sql_mode='".$sql_mode_altered."'");
+  }
 }
 
 /**