postgresql 实现取出分组中最大的几条数据
作者：紫晶城
这篇文章主要介绍了postgresql 实现取出分组中最大的几条数据，具有很好的参考价值，希望对大家有所帮助。一起跟随小编过来看看吧
看代码吧~
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
其中
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
执行结果：
添加行序号：ROW_NUMBER () OVER (ORDER BY A.bsm ASC) AS 序号
分组添加序号：ROW_NUMBER () OVER (PARTITION BY xzqdm ORDER BY A.bsm ASC) AS 序号
补充：pgsql 表随机取几条数据
取100条
select * from map_route_info_composite order by random() limit 100
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。如有错误或未考虑完全的地方，望不吝赐教。