看看这个，看看有没有一个连接的更新。否则，可以使用merge语句，只包含update部分，而不包含insert部分。那可能更容易写。
可能是这样的：

update mc
set eligible = case when pp.partner_id is not null then 'Y' when pp2.partner_id is null then 'N' end
from

$env_tech_db.tbl_tech_mpxn_cohort  mc
left join $env_tech_db.tbl_tech_mct mct 
on mc.mpxn = mct.mpxn 
left join $env_tech_db.tbl_tech_partner_priority pp
on mct.partner = pp.partner_id

left join $env_tech_db.tbl_tech_mct mct2 
on mc.mpxn = mct2.mpxn
left join $env_tech_db.tbl_tech_partner_priority pp2
on mct2.partner = pp2.partner_id

where pp.status = 'Include' and mct.status     in ('0','0S','0Z')) 
and pp2.status = 'Include' and mct2.status in ('0')

您遇到的问题是，要更新的表也用于联接中(或者在这种情况下，在exists子查询的where子句中引用）

我不认为databricks支持如此复杂的表达式。您可以使用两个更新：

update $env_tech_db.tbl_tech_mpxn_cohort mc
    set eligible = 'N';

update $env_tech_db.tbl_tech_mpxn_cohort  mc
    set eligible = 'Y'
    where exists (select 1
                  from $env_tech_db.tbl_tech_mct mct join
                       $env_tech_db.tbl_tech_partner_priority pp
                       on mct.partner = pp.partner_id
                  where mc.mpxn = mct.mpxn and pp.status = 'Include' and
                        mct.status in ('0','0S','0Z')
                 ) or
          not exists (select 1
                      from $env_tech_db.tbl_tech_mct mct join
                           $env_tech_db.tbl_tech_partner_priority pp
                           on mct.partner = pp.partner_id
                      where mc.mpxn = mct.mpxn and pp.status = 'Include' and 
                            mct.status in ('0')
                      ) ;