select t.orgname,t.type_name,ifnull(sum(t.stoptime),0) as stoptime

from(SELECT

o.keycode  as orgcode,

o.name as orgname,

case when wh.typeid=1 then '故障工单' else '保养工单' end as type_name,

wh.stoptime

FROM

workorderhistory wh

left join organization o on wh.orgid=o.id

where wh.typeid in (1,3)

  and wh.orgid =25

  and (DATE_FORMAT(wh.technicaldate,'%Y-%m-%d') between '2021-07-01' and '2021-07-19')  

)t

group by t.orgname,t.type_name

这个SQL里面type_name的字段，在Navicat中显示的是正常的值，但是在设计器中预览就变成了"????"的值，数据库是MySQL5.7，应该是SQL的问题还是设计器的问题？