SQL Stuff XML，GROUP BY

Question

我有以下查询，它通过SQL的XML函数返回这些结果：

它已成功按PO编号分组，但我试图让XML列表也按运营商分组......

所以带有运营商fedex的行只会显示123456 for alltrackingno，带有运营商ups的行会显示ups987653 for alltrackingno。

尝试了各种各样的加入变种而没有成功。

提前谢谢！

select ponumber,
       case
            when ca_type = 'FEX'
            then 'fedex'
            when ca_type = 'UPS'
            then 'ups' else ''
            end as carrier,
       stuff((select ', ' + ltrim(rtrim(trackingno)) from box ee
       where ltrim(rtrim(trackingno)) <> '' and ee.orderno=e.orderno
       order by box for xml path('')), 1, 2, '') as alltrackingno
       from box e right join carrier on e.shiplist =  carrier.ca_code
       right join cms on e.orderno = cms.orderno
       where cms.custnum = 100 and ltrim(rtrim(trackingno)) <> ''
       and emailedtracking = 0
       group by e.orderno, ponumber, ca_type