Sql如何获得MAX和MIN Historydata以及相应的用户

Question

I have this table with HistoryDate and User. I need to query Max(Historydate), User correspondind to Maxdate, Min(HistoryDate), User corresponding to MinDate for each ReviewID like this

   ModifiedDate |ModifiedBy| CreatedDate  | CreatedBy |ReviewId
  2/16/17 12:58 | Susan    | 2/7/17 15:39 | John      | 1
  2/15/17 13:25 | Sam      | 2/9/17 20:27 | John      | 2

I am able to query it using table variable but wondering any other way to get it.

Answer 1

Have a go at using sub-queries in the FROM clause to get each min and max. In order to get only the min/max for each review, you'll need to use GROUP BY ReviewID like so:

SELECT max.date AS maxDate, max.user AS maxUser, min.date AS minDate, 
min.user AS minUser
FROM (
    (SELECT MAX(HistoryDate) date, user, ReviewID
    FROM HistoryTable
    GROUP BY ReviewID) max
        JOIN 
    (SELECT MIN(HistoryDate) date, user, ReviewID
    FROM HistoryTable
    GROUP BY ReviewID) min
        ON max.ReviewID = min.ReviewID
)

Answer 2

Hi after few days of playing with script this worked for me.

SELECT ModifiedDate, ModifiedBy, CreatedDate ,CreatedBy,  crt.ReviewID 
     FROM   (SELECT  HistoryDate  CreatedDate, ReviewId,   [User] CreatedBy FROM HistoryTable 
        WHERE HistoryDate in (SELECT min(HistoryDate)  FROM  HistoryTable GROUP BY ReviewID )) crt
INNER JOIN
    (SELECT HistoryDate  ModifiedDate, ReviewID, [User] ModifiedBy FROM  HistoryTable 
        WHERE HistoryDate in (SELECT Max(HistoryDate)  FROM HistoryTable GROUP BY ReviewID )) Modi
ON crt.ReviewId = Modi.ReviewID
         ORDER BY crt.ReviewID