Add a default _from_tables() method to CI_DB_query_builder and remove it from most of the drivers
diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index 7a0ea0c..3ed5562 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -1475,6 +1475,24 @@
// --------------------------------------------------------------------
/**
+ * From Tables
+ *
+ * This public function implicitly groups FROM tables so there is no confusion
+ * about operator precedence in harmony with SQL standards
+ *
+ * @param array
+ * @return string
+ */
+ protected function _from_tables($tables)
+ {
+ is_array($tables) OR $tables = array($tables);
+
+ return (count($tables) === 1) ? $tables[0] : '('.implode(', ', $tables).')';
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
* Get UPDATE query string
*
* Compiles an update query and returns the sql