How To get the First Row Form SQL Group Query?

Question

I have a problem in writing a query.

I'd like to select the first row of each set of rows grouped

My table is Transactions:

userID | Date     | StoreID 
---------------------------
     1 | 8-9-2013 | 10
     1 | 9-9-2013 | 10
     1 | 10-9-2013| 20
     2 | 7-9-2013 | 30
     2 | 8-9-2013 | 10
     2 | 9-9-2013 | 20
     1 | 11-9-2013| 10
     2 | 10-9-2013| 20

and I try to this SQL statement:

Select 
    tr.userID , Min(tr.TransactionDate) FirstDate
From 
    Transactions tr 
Group By 
    tr.userID 

I get this output:

userID | Date     
------------------
     1 | 8-9-2013 
     2 | 7-9-2013

But I need the Store ID in every first transaction.

I need it to be like that

 userID | Date    |  StoreID
-------------------------
     1 | 8-9-2013 |  10
     2 | 7-9-2013 |  30

Please any one can help me

Solution 1

SQL Fiddle

MS SQL Server 2008 Schema Setup:

CREATE TABLE Transactions
    ([userID] int, [Date] datetime, [StoreID] int)
;

INSERT INTO Transactions
    ([userID], [Date], [StoreID])
VALUES
    (1, '2013-08-09 00:00:00', 10),
    (1, '2013-09-09 00:00:00', 10),
    (1, '2013-10-09 00:00:00', 20),
    (2, '2013-07-09 00:00:00', 30),
    (2, '2013-08-09 00:00:00', 10),
    (2, '2013-09-09 00:00:00', 20),
    (1, '2013-11-09 00:00:00', 10),
    (2, '2013-10-09 00:00:00', 20)
;

Query 1:

SELECT
    tr.userID , Min(tr.Date) FirstDate , tr2.storeid
FROM
    Transactions tr
inner join Transactions tr2 on tr.userid = tr2.userid and 
                              tr2.date = (select top 1 date 
                                          from transactions t 
                                          where t.userid = tr2.userid
                                          order by date asc)
GROUP BY
    tr.userID, tr2.storeid

Results:

| USERID |                     FIRSTDATE | STOREID |
|--------|-------------------------------|---------|
|      1 | August, 09 2013 00:00:00+0000 |      10 |
|      2 |   July, 09 2013 00:00:00+0000 |      30 |

Solution 2

You could use Row_Number().

select UserId, Date, StoreId from  (select row_number() over(partition
by UserId order by date) as RowNumber,   UserId, Date, StoreId from
Transactions  ) as View1 where  RowNumber = 1

http://sqlfiddle.com/#!6/e536a/7

Solution 3

You could use a sub-query

SELECT  TR1.userID
        ,TR1.TransactionDate
        ,TR1.StoreID
FROM    Transactions tr1
INNER JOIN
        (
        Select 
            tr.userID 
            ,Min(tr.TransactionDate) AS FirstDate
        From 
            Transactions tr 
        Group By 
            tr.userID 
        ) SQ
ON      TR1.userID = SQ.userID 
AND     TR1.TransactionDate = SQ.FirstDate