title: Using WMSYS.WM_CONCAT with Oracle XE 10g
body: <p>When I try to use WMSYS.WM_CONCAT with Oracle XE 10g, I receive a compilation error: <code>ORA-00904: "WMSYS"."WM_CONCAT": invalid identifier</code>.  Can anyone verify that this is indeed due to XE lacking this (undocumented) feature?  If so, is there anyway to enable it in XE?</p>