sql-server - SQL Server 过度查询

Question

我的查询返回每个用户 ID 的最新条目，但我需要它返回每个用户 ID 和任务名的最新条目。我尝试使用 group by，但出现错误。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

您应该将PARTITION BY UserID替换为PARTITION BY UserID, TaskName：

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

如果没有要测试的数据和表格结构，我只能假设您真正想要实现的目标，但它可能看起来像这样：

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