如何查询 sql 以获取每个用户的最新记录日期 [英] how do I query sql for a latest record date for each user

问题描述

我有一个表格，它是关于用户何时登录的集合条目.

I have a table that is a collection entries as to when a user was logged on.

username, date,      value
--------------------------
brad,     1/2/2010,  1.1
fred,     1/3/2010,  1.0
bob,      8/4/2009,  1.5
brad,     2/2/2010,  1.2
fred,     12/2/2009, 1.3

etc..

如何创建一个查询，为我提供每个用户的最新日期?

How do I create a query that would give me the latest date for each user?

更新:我忘记了我需要一个与最新日期一致的值.

Update: I forgot that I needed to have a value that goes along with the latest date.

推荐答案

select t.username, t.date, t.value
from MyTable t
inner join (
    select username, max(date) as MaxDate
    from MyTable
    group by username
) tm on t.username = tm.username and t.date = tm.MaxDate

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