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How to get the last row from a table using JOIN

I have a join of 5 tables to get jobs posted by each member having about 15 columns. But for the sample code, I took only two tables from them.

SELECT TOP 5 
    dbo.MemberMst.MemberID, dbo.MemberMst.fname, 
    dbo.TaskMst.TaskMstID, dbo.TaskMst.OnDate, dbo.TaskMst.Description
FROM   
    dbo.MemberMst 
LEFT JOIN
    dbo.TaskMst ON dbo.MemberMst.MemberID = dbo.TaskMst.MemberID

Output:

MemberID fname  TaskMstID    OnDate                   Description
3    Ursula     NULL         NULL                      NULL
84   Opeyemi    30           2012-09-18 00:00:00.000     asd
85   test       21           2012-09-18 10:30:46.900     aaa
85   test       22           2012-09-18 10:31:04.967     eeee
85   test       23           2012-09-18 10:31:26.640     vvvv

In the above query, I get 3 rows for MemberID=85which posted 3 tasks, but I only need one task from this member, which is the last. How to get the last task sent by a member so that the result is: -

MemberID fname  TaskMstID OnDate                Description
3    Ursula     NULL      NULL                   NULL
84   Opeyemi    30        2012-09-18 00:00:00.000   asd
85   test       23        2012-09-18 10:31:26.640   vvvv

I mean only one entry for each memberIDhaving tasks?

Help evaluate ..!

Thanks in advance...!

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4 answers

SQL Server 2008, Window Functions.

- :

SELECT  c.MemberID, c.fname, c.TaskMstID, c.OnDate, c.Description
FROM
    (
        SELECT  a.MemberID, a.fname,
                b.TaskMstID, b.OnDate, b.Description,
                ROW_NUMBER() OVER (Partition BY a.MemberID ORDER BY b.OnDate DESC) RN
        FROM    MemberMst a
                LEFT JOIN TaskMst b
                    ON a.MemberID = b.MemberID
    ) c
WHERE c.RN = 1
+4
;With Cte1  AS
(

SELECT  top 5 dbo.MemberMst.MemberID, dbo.MemberMst.fname, dbo.TaskMst.TaskMstID, dbo.TaskMst.OnDate, dbo.TaskMst.Description
FROM   dbo.MemberMst left JOIN
dbo.TaskMst ON dbo.MemberMst.MemberID = dbo.TaskMst.MemberID
),
Cte2 As
(   SELECT Rn = Row_Number() Over(Partition by MemberId Order By OnDate Desc), *
    From Cte1

)
Select * 
From Cte2 
Where Rn = 1

. .

+3

You just need to use Group BY () Offer with MAX () function

with CTE as(
    SELECT TOP 5 
        dbo.MemberMst.MemberID, 
        dbo.MemberMst.fname, 
        dbo.TaskMst.TaskMstID, 
        dbo.TaskMst.OnDate, 
        dbo.TaskMst.Description
    FROM
        dbo.MemberMst left 
        JOIN dbo.TaskMst 
        ON dbo.MemberMst.MemberID = dbo.TaskMst.MemberID)

select dbo.MemberMst.MemberID, 
        dbo.MemberMst.fname, 
        dbo.TaskMst.TaskMstID, 
        max(dbo.TaskMst.OnDate) as OnDate, 
        dbo.TaskMst.Description
from CTE
group by MemberID
+1
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You can divide by MemberID and then take a rank above it and select only the top ranked item.

Additional MSDN Information

Try something like this

WITH MyCte AS 
(SELECT  top 5 dbo.MemberMst.MemberID, dbo.MemberMst.fname, dbo.TaskMst.TaskMstID, dbo.TaskMst.OnDate, dbo.TaskMst.Description,
        ROW_NUMBER() OVER (PARTITION BY dbo.MemberMst.MemberID ORDER BY dbo.TaskMst.OnDate DESC) AS RowNum 
FROM   dbo.MemberMst 
left JOIN dbo.TaskMst ON dbo.MemberMst.MemberID = dbo.TaskMst.MemberID)
SELECT  *
FROM    MyCte
WHERE   RowNum > 0

UPDATE: Changed for ROW_NUMBER () instead of RANK () to avoid the problem with multiple rows with the same rank.

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