Need help finding the correct T-SQL Query
I am not quite sure how to go about doing this. Basically I have have a table like this
UserId DateRequested Approved ApprovedBy Notes
------------ ----------------------- -------- ----------- -----
1 2011-05-26 0 NULL NULL
1 2011-05-27 0 NULL NULL
1 2011-05-28 0 NULL NULL
1 2011-06-05 0 NULL NULL
1 2011-06-06 0 NULL NULL
1 2011-06-25 0 NULL NULL
Which basically contains the days an employee requests a holiday. Now, when a day or days is granted, this data needs to be copied over to a table of the form
UserId DateFrom DateTo
So basically for the above开发者_运维技巧 data i want:
UserId DateFrom DateTo
-------------------------------
1 2011-05-26 2011-05-28
1 2011-06-05 2011-06-06
1 2011-06-25 2011-06-25
I.e I want consecutive days in the DateFrom and DateTo. Now I am not sure how to do this without using a while loop. This is SQL, So i would prefer a non-iterative solution.
Please advise!!!
;WITH cte AS
(
SELECT *,
DATEDIFF(DAY,0,DateRequested)-
ROW_NUMBER() OVER (PARTITION BY UserId ORDER BY DateRequested) AS Grp
FROM YourTable
WHERE Approved = 1 /*Presumably - but your example data doesn't show this.*/
)
SELECT UserId,
MIN(DateRequested) AS DateFrom,
MAX(DateRequested) AS DateTo
FROM cte
GROUP BY UserId,Grp
In Oracle PL/SQL it would be written as follows:
WITH cte
AS (SELECT a.*,
daterequested - TRUNC (SYSDATE)
- ROW_NUMBER ()
OVER (PARTITION BY UserId ORDER BY DateRequested)
AS Grp
FROM yourtable a
WHERE Approved = 0)
SELECT UserId, MIN (DateRequested) AS DateFrom, MAX (DateRequested) AS DateTo
FROM cte
GROUP BY UserId, Grp;
精彩评论