Posgresql按日期和特定id选择前x行
我有这张桌子:Posgresql按日期和特定id选择前x行,sql,postgresql,select,greatest-n-per-group,Sql,Postgresql,Select,Greatest N Per Group,我有这张桌子: +----+--------+--------+-----------+----------------------------+ | id | type | amount | dealer_id | date | +----+--------+--------+-----------+----------------------------+ | 12 | sub_s | 29.00 | 502 | 2020-05
+----+--------+--------+-----------+----------------------------+
| id | type | amount | dealer_id | date |
+----+--------+--------+-----------+----------------------------+
| 12 | sub_s | 29.00 | 502 | 2020-05-21 10:05:41.725+02 |
| 11 | sub_pe | 79.00 | 501 | 2020-05-20 09:05:41.725+02 |
| 10 | sub_pe | 79.00 | 501 | 2020-05-19 09:05:41.725+02 |
| 9 | sub_pe | 79.00 | 501 | 2020-05-18 09:05:41.725+02 |
| 8 | sub_pe | 79.00 | 501 | 2020-05-17 09:05:41.725+02 |
| 7 | sub_pe | 79.00 | 501 | 2020-05-16 09:05:41.725+02 |
| 6 | sub_pe | 79.00 | 501 | 2020-05-15 09:05:41.725+02 |
| 5 | sub_pe | 79.00 | 501 | 2020-05-14 09:05:41.725+02 |
| 4 | sub_pe | 79.00 | 501 | 2020-05-13 09:05:41.725+02 |
| 1 | sub_pe | 79.00 | 501 | 2020-05-12 09:05:41.725+02 |
+----+--------+--------+-----------+----------------------------+
如何为每个经销商id仅选择前6行按日期订购ASC
结果是:
+----+--------+--------+-----------+----------------------------+
| id | type | amount | dealer_id | date |
+----+--------+--------+-----------+----------------------------+
| 12 | sub_s | 29.00 | 502 | 2020-05-21 10:05:41.725+02 |
| 8 | sub_pe | 79.00 | 501 | 2020-05-17 09:05:41.725+02 |
| 7 | sub_pe | 79.00 | 501 | 2020-05-16 09:05:41.725+02 |
| 6 | sub_pe | 79.00 | 501 | 2020-05-15 09:05:41.725+02 |
| 5 | sub_pe | 79.00 | 501 | 2020-05-14 09:05:41.725+02 |
| 4 | sub_pe | 79.00 | 501 | 2020-05-13 09:05:41.725+02 |
| 1 | sub_pe | 79.00 | 501 | 2020-05-12 09:05:41.725+02 |
+----+--------+--------+-----------+----------------------------+
具有行数窗口功能:
select t.id, t.type, t.amount, t.dealer_id, t.date
from (
select * ,
row_number() over (partition by dealer_id order by date) rn
from tablename
) t
where t.rn <= 6