filter的時間過濾有關問題

filter的時間過濾問題
ls_filter=ls_filter+" and to_Date(h.enddate,'yyyymmdd h24:mi:ss')>=to_date(sysdate,'yyyymmdd h24:mi:ss')"

運行的時候提示:
')'expected to close expression aftber function

但是好像不缺右括號啊

------解決方案--------------------------------------------------------
ls_filter=ls_filter+" and string(h.enddate,'yyyymmdd h24:mi:ss')>=string(sysdate,'yyyymmdd h24:mi:ss')"


用setfilter過濾時間我一般都是這樣過濾的： 
ls_filter = "string(h.enddate,'yyyymmdd h24:mi:ss') >= '"+string(sysdate,'yyyymmdd h24:mi:ss')+"'"
dw_1.setfilter(ls_filter)
dw_1.filter()