可参考以下SQL,员工表不存上级,可通过员工任职的职位->职位的上级->任职于上级职位的员工,找到员工对应的上级领导(根据实际情况分析兼职和主职)

SELECT a.fname_l2,c.fname_l2,d.fname_l2,f.fname_l2 FROM
T_BD_PERSON a
left join T_HR_EMPORGRELATION b on a.fid=b.fpersonid and b.FLEFFDT ={ts '2199-12-31'}
left join T_ORG_POSITION c on b.FPOSITIONID =c.fid
left join T_ORG_POSITION d on c.FPARENTID =d.fid
left join T_HR_EMPORGRELATION e on d.fid=e.fpositionid and e.FLEFFDT ={ts '2199-12-31'}
left join T_BD_PERSON f on e.FPERSONID =f.fid
where a.fnumber='EMP000025'