Feature 1255: modification in sql queries

- manage random function
    - manage regex syntax
    - manage quote (single instead of double)
    - manage interval

git-svn-id: http://piwigo.org/svn/trunk@4367 68402e56-0260-453c-a942-63ccdbb3a9ee

include/filter.inc.php

@@ -96,8 +96,7 @@ WHERE ';
   category_id  IN ('.$filter['visible_categories'].') and';
     }
   $query.= '
-    date_available >= SUBDATE(
-      CURRENT_DATE,INTERVAL '.$filter['recent_period'].' DAY)';
+    date_available >= '.pwg_db_get_recent_period_expression($filter['recent_period']);
 
     $filter['visible_images'] = implode(',', array_from_query($query, 'image_id'));