如何选择组中的最新记录？

Question

我有一个记录集如下：

company_id      po_date     po_number       supplier_company_id

1             01/01/2017        1000          20
1             02/01/2017        1001          20
1             03/01/2017        1002          20
2             01/02/2017        1005          30
2             02/02/2017        1006          30
2             03/02/2017        1007          30

我希望返回每个company_id的最新日期的记录

company_id      po_date     po_number       supplier_company_id

1              03/01/2017       1002        20
2              03/02/2017       1007        30

Answer 1

使用此

select * from 
(select t.*,row_number() over (partition by company_id order by po_date desc) rn
from your_table t)
where rn=1