SQL查询:仅显示每个集合中的最新ID [英] SQL Query: Display only latest Id from each set

问题描述

我有以下SQL表:

Name       Description   Id   UserId   CreatedDate
UserSet1   Desc1         1    Abc      06/01/2018
UserSet1   Desc2         2    Def      06/02/2018
UserSet2   Desc for 2    5    NewUser  06/04/2018
UserSet2   Desc for 2    7    NewUser  06/19/2018

我要从上表中提取的只是每个名称的最新ID，以便获得以下输出

What I want to extract from the above table is just the latest Id for each Name so that I could get the following output

Name      Description    Id    UserId    CreatedDate
UserSet1  Desc2          2     Def       06/01/2018
UserSet2  Desc for 2     7     NewUser   06/19/2018

由于Id 2& 7是表中UserSet1&的最新条目. UserSet2，我想显示它而不是表中的所有条目.

Since Id 2 & 7 are the latest entries in the table for UserSet1 & UserSet2, I would like to display that instead of all the entries in the table.

任何输入都如何获得所需的结果.

Any inputs how can I get the desired result.

我愿意接受直接返回输出的解决方案或任何linq(C#)解决方案.即返回整个数据集，然后使用linq过滤上述内容.

I am open for solutions directly returning the output or any linq (C#) solutions as well. Ie returning the entire dataset and then using linq to filter the above.

推荐答案

感谢大家指出正确的方向.我已经使用下面的Linq和C#代码进行了此工作:

Thanks everyone for pointing to right direction. I have got this working with the below code of Linq and C#:

 var results = response.GroupBy(row => row.Name)
                   .SelectMany(g => g.OrderByDescending(row => row.Id).Take(1));

对于最初的测试，这似乎是可行的.让我知道您是否认为这已经成为问题.

For the initial tests this seems to be working. Let me know if you think this has come issues.

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