postgresql 实现取出分组中最大的几条数据

WITH Name AS (

  SELECT

   *

  FROM

   (

    SELECT

     xzqdm,

     SUBSTRING (zldwdm, 1, 9) xzdm,

     COUNT (*) sl

    FROM

     sddltb_qc

    WHERE

     xzqdm IN ( '130432' , '210604' )

    GROUP BY

     xzqdm,

     SUBSTRING (zldwdm, 1, 9)

   ) AS A

  ORDER BY

   xzqdm,

   xzdm,

   sl

) SELECT

  xzqdm,

  xzdm,

  sl

FROM

  (

   SELECT

    *, ROW_NUMBER () OVER (

     PARTITION BY xzqdm

     ORDER BY

      sl DESC

    ) AS Row_ID

   FROM

    Name

  ) AS A

WHERE

  Row_ID <= 2

ORDER BY

  xzqdm

select * from ( select xzqdm, substring (zldwdm,1,9) xzdm, count (*) sl from sddltb_qc where xzqdm in ( '130432' , '210604' ) group by xzqdm, substring (zldwdm,1,9)) as a order by xzqdm,xzdm,sl

select * from map_route_info_composite order by random() limit 100