在 SQL Server 中使用 2 个不同的列进行分组

Question

我有如下数据

ID  Stat    Date
1   1       2009-06-01
2   1       2009-06-20
3   1       2009-06-10
4   2       2009-06-10

O/P 是这样的..

ID     Stat   CDate
2      1      2009-06-20
4      2      2009-06-10

我已尝试使用以下查询但未成功，请提出建议。

Select Distinct stat,MAX(Cdate) dt,id  From testtable
Group By stat,id

得到了解决方案..

Select f1.id,f1.stat,f1.cdate From testtableas F1 Join(Select stat,MAX(cdate) as dt from testtable group by stat) as F2 On f2.stat=F1.stat and f2.dt=f1.cdate

Answer 1

SELECT t1.id, t1.stat, t1.date
FROM testtable t1
JOIN (SELECT stat, MAX(date) date FROM testtable GROUP BY stat) t2 ON t1.stat = t2.stat AND t1.date = t2.date
GROUP BY stat