如何结合其他条件查找每个产品的最新日期时间

尝试:

SELECT
    p.ProductID, p.ProductName, dt.MaxTimeStamp
    FROM Product p
        LEFT OUTER JOIN (SELECT
                            ProductID, MAX(TimeStamp) AS MaxTimeStamp
                            FROM StateLog
                            WHERE State = 0
                            GROUP BY ProductID
                        ) dt ON p.ProductID =dt.ProductID 
    ORDER BY p.ProductName

或者只是:

SELECT
   ProductID, MAX(TimeStamp) AS MaxTimeStamp
   FROM StateLog
   WHERE State = 0
   GROUP BY ProductID

WITH ProductTimeStamps AS
(
   SELECT ProductID, Max(TimeStamp) FROM SateLog WHERE State=0 GROUP BY ProductID
)
SELECT sl.StateLogID, sl.ProductID, sl.TimeStamp
FROM StateLog sl
INNER JOIN ProductTimeStamps pts ON pts.ProductID = sl.ProductID AND pts.TimeStamp = sl.TimeStamp
WHERE sl.State = 0