如何在Postgres中的分区上实现Oracle count（distinct）

Postgres不count(distinct)直接支持。但是您可以使用子查询来实现它：

select . . .,
       sum( (seqnum_tm = 1)::int) as mob_segments_count ,
       sum( (seqnum_tr = 1)::int) as countries_count
from (select . . .,
             row_number() over (partition by pm.trans_id, pm.country_reg_region_cd order by pm.country_reg_region_cd) as seqnum_tr,
             row_number() over (partition by pm.trans_id, pm.mobseg_state order by pm.pm.mobseg_state) as seqnum_tm
      . . .
     ) . . .

这个想法很简单。计算row_number()的partition by键和独特的列。然后，只需将值等于“ 1”的次数相加即可。这需要一个子查询，因为您不能嵌套窗口函数。