SQL Server查询

Question

我的查询返回每个用户标识的最新条目，但我需要它返回每个用户标识和任务名称的最新条目。我试图用group by，但是我得到一个错误。有什么我做错了吗？谢谢！

SELECT UserId, TaskName, First, Last, email, ValueDate, Analysis 
FROM (SELECT UserId, TaskName, First, Last, 
email, ValueDate, Analysis, 
ROW_NUMBER() OVER(PARTITION BY UserID 
ORDER BY ValueDate DESC) AS rk 
FROM MyTable) AS L 
WHERE rk = 1 

Answer 1

此时应更换PARTITION BY用户ID与PARTITION BY用户ID，任务名称：

SELECT UserId, TaskName, First, Last, email, ValueDate, Analysis 
FROM (SELECT UserId, TaskName, First, Last, 
email, ValueDate, Analysis, 
ROW_NUMBER() OVER(PARTITION BY UserID, TaskName 
ORDER BY ValueDate DESC) AS rk 
FROM MyTable) AS L 
WHERE rk = 1 

Answer 2

没有有一些数据，以测试和表格结构，我只能假设你真的想实现什么，但它可能是一些看起来像这样的：

SELECT UserId, TaskName, First, Last, email, max(ValueDate), Analysis 
FROM MyTable 
GROUP BY UserId, TaskName, First, Last, email, Analysis 
ORDER BY MAX(ValueDate) DESC