birt报表分组问题

为什么我在before open 中写grpop by sql后 报表就无法引用输出列，提示xxx列不存在，而去除了就ok,在线等 。。。
this.queryText = this.queryText+=(" where 1=1"," WHERE CREATE_TIME > STR_TO_DATE('"+params["rp_fromdate"].value+"', '%Y-%m-%d')"+
" AND CREATE_TIME < STR_TO_DATE('"+params["rp_todate"].value+"'+INTERVAL 1 day, '%Y-%m-%d')");
if(!"".equals(params["rp_firstServiceType"].value)){
this.queryText+=" AND SERVICE_TYPE_FIRST_ID IN ("+params["rp_firstServiceType"].value+")"
}
if(!"".equals(params["rp_secSerType"].value)){
this.queryText+=" AND cast(REPLACE (t.SERVICE_TYPE_SECOND_ID,'-','') AS signed) IN ("+params["rp_secSerType"].value+")";
}