如何在MSSQL中获得最早的一列并获得最新的另一列

Question

When I run this query :

select * from customertravel where PersonID in (1,2,7)

I get this :

But I want to filter results to be like this :

How should I modify that query to get first arrive date and last leave date? I know I need to do some group by but I couldn't figure how to use it.. Thnkas in advance..

Answer 1

Supposing your ArriveDate and LeaveDate are dates and not strings or so, you could try the following:

SELECT   PersonID,
         Name,
         City,
         MIN(ArriveDate),
         MAX(LeaveDate)
FROM     customertravel
WHERE    PersonID IN (1, 2, 7)
GROUP BY PersonID,
         Name,
         City;

Answer 2

You need to group by all columns except the dates, and find MIN and MAX . Just in case your dates are in German format you need to convert them before calculating aggregate:

SELECT
    PersonID,
    Name,
    City,
    MIN(CONVERT(DATE, ArriveDate, 104)) AS FirstArriveDate,
    MAX(CONVERT(DATE, LeaveDate, 104)) AS LastLeaveDate
FROM customertravel
WHERE PersonID IN (1, 2, 7)
GROUP BY PersonID, Name, City