Merge pull request #56 from stefanklug/postgresDateFixes

Reopened on feature branch: Fix Postgres Date Add/Sub functions for dynamic values

lib/Doctrine/DBAL/Platforms/PostgreSqlPlatform.php

@@ -99,22 +99,22 @@ class PostgreSqlPlatform extends AbstractPlatform
 
     public function getDateAddDaysExpression($date, $days)
     {
-        return "(" . $date . "+ interval '" . $days . " day')";
+        return "(" . $date ." + (" . $days . " || ' day')::interval)";
     }
 
     public function getDateSubDaysExpression($date, $days)
     {
-        return "(" . $date . "- interval '" . $days . " day')";
+        return "(" . $date ." - (" . $days . " || ' day')::interval)";
     }
 
     public function getDateAddMonthExpression($date, $months)
     {
-        return "(" . $date . "+ interval '" . $months . " month')";
+        return "(" . $date ." + (" . $months . " || ' month')::interval)";
     }
 
     public function getDateSubMonthExpression($date, $months)
     {
-        return "(" . $date . "- interval '" . $months . " month')";
+        return "(" . $date ." - (" . $months . " || ' month')::interval)";
     }
 
     /**