在SQL中以ID，Month级别准备数据

Question

我有一个像这样的表：

ID  Date
1   10/04/2015
1   28/04/2015
1   14/07/2015
1   30/07/2015
1   30/08/2015
2   10/04/2016
2   28/04/2016
2   14/05/2016
2   30/05/2016

但我想实现如下：

ID  Date
1   28/04/2015
1   30/07/2015
1   30/08/2015
2   28/04/2016
2   30/05/2016

请你帮助我好吗 。

Answer 1

试试这个：

select * from (
    select id,
           [Date],
           row_number() over (partition by id, datepart(month, [date]) order by [Date] desc) [rn]
    from (
    select id, 
           --date convrsion, 103 - British/French - your style
           convert(date, [date], 103) [Date]
    from @MyTable
    ) a
) b where rn = 1 

Answer 2

我没有真正得到预期结果的逻辑，但下面的查询将起作用。

SELECT *
FROM yourTable 
WHERE DAY([Date])>=28;

见How to get Day, Month and Year Part from DateTime in Sql Server