=== modified file 'modules/date/date_api_sql.inc'
--- modules/date/date_api_sql.inc	2009-10-14 10:14:29 +0000
+++ modules/date/date_api_sql.inc	2010-01-02 16:39:10 +0000
@@ -326,7 +326,7 @@
       case 'mysql':
       case 'mysqli':
         $replace = array(
-          'Y' => '%Y', 'y' => '%y',
+          'Y' => '%Y', 'y' => '%y', 'o' => '%Y',
           'm' => '%m', 'n' => '%c',
           'd' => '%%d', 'j' => '%e',
           'H' => '%H',
@@ -338,7 +338,7 @@
         return "DATE_FORMAT($field, '$format')";
       case 'pgsql':
         $replace = array(
-          'Y' => 'YYYY', 'y' => 'Y',
+          'Y' => 'YYYY', 'y' => 'Y', 'o' => '%Y',
           'm' => 'MM', 'n' => 'M',
           'd' => 'DD', 'j' => 'D',
           'H' => 'HH24',
@@ -685,7 +685,7 @@
         break;
       case('week'):
         $formats['display'] = 'F j Y (W)';
-        $formats['sql'] = 'Y-\WW';
+        $formats['sql'] = 'o-\WW';
         break;
     }
     return $formats[$type];