Question

I have a SQL table where I need to get the number for the final row with a date and count the number of previous rows even if they don’t have a date in either.

e.g

02/01/2011
03/01/2011
09/01/2011
NULL
10/10/2011
NULL

This table should return the number 5 for the 5th record

NULL
NULL
NULL
09/01/2011
NULL
10/10/2011
NULL

This table should return 6

Thank you in advance

J

—– Update ——
Just a little more information

The table its self represents units of work complete (milestones) and links to a parent table which represents units of work. In the milestone table it contains dates, Parent Work Id and a milsestone ID.

From the first example

ParentID    MilestoneID    Date
1234        123            02/01/2011
1234        124            03/01/2011
1234        125            09/01/2011
1234        126            NULL
1234        127            10/10/2011
1234        128            NULL

Hope this helps

—– Update 2 —–

The closest I got was this

SELECT TOP 1
    Num
FROM
    (
    SELECT
        ROW_NUMBER()OVER(ORDER BY ParentID) AS Num,
        Date

    FROM
        Milestone
    WHERE
        Milestone.ParentID = 1234
) AS MilestoneStones

WHERE
Date IS NOT NULL
ORDER BY
Num DESC

But with a large data set and other things attaching to it it got very slow
Was hoping that I could get something better

Thank you

J

Answer 1

I am going to assume some ordering column called ord and a date column called dt:

Naively:

SELECT COUNT(*)
FROM tbl
WHERE ord <= (SELECT MAX(ord) FROM tbl WHERE dt IS NOT NULL)

With your updated data, see how this performs:

https://data.stackexchange.com/stackoverflow/q/109223/

DECLARE @tbl AS TABLE (ParentID INT, MilestoneID INT, [Date] DATETIME);
INSERT INTO @tbl VALUES (1234,        123,            '02/01/2011');
INSERT INTO @tbl VALUES (1234,        124,            '03/01/2011');
INSERT INTO @tbl VALUES (1234,        125,            '09/01/2011');
INSERT INTO @tbl VALUES (1234,        126,            NULL);
INSERT INTO @tbl VALUES (1234,        127,            '10/10/2011');
INSERT INTO @tbl VALUES (1234,        128,            NULL);

WITH LastCompleted AS (
    SELECT ParentID, MAX(MilestoneID) AS MAXMilestoneID
    FROM @tbl AS Milestone
    WHERE [Date] IS NOT NULL
    GROUP BY ParentID
)
SELECT LastCompleted.ParentID, COUNT(*) AS NumMilestones
FROM LastCompleted
INNER JOIN @tbl AS Milestone
    ON LastCompleted.ParentID = Milestone.ParentID
    AND LastCompleted.MAXMilestoneID >= Milestone.MilestoneID
GROUP BY LastCompleted.ParentID;