T-SQL: Paging WITH TIES

Question

I am trying to implement a paging routine that's a little different.

For the sake of a simple example, let's assume that I have a table defined and populated as follows:

DECLARE @Temp TABLE
(
    ParentId    INT,
    [TimeStamp] DATETIME,
    Value       INT
);

INSERT INTO @Temp VALUES (1, '1/1/2013 00:00', 6);
INSERT INTO @Temp VALUES (1, '1/1/2013 01:00', 7);
INSERT INTO @Temp VALUES (1, '1/1/2013 02:00', 8);
INSERT INTO @Temp VALUES (2, '1/1/2013 00:00', 6);
INSERT INTO @Temp VALUES (2, '1/1/2013 01:00', 7);
INSERT INTO @Temp VALUES (2, '1/1/2013 02:00', 8);
INSERT INTO @Temp VALUES (3, '1/1/2013 00:00', 6);
INSERT INTO @Temp VALUES (3, '1/1/2013 01:00', 7);
INSERT INTO @Temp VALUES (3, '1/1/2013 02:00', 8);

TimeStamp will always be the same interval, e.g. daily data, 1 hour data, 1 minute data, etc. It will not be mixed.

For reporting and presentation purposes, I want to implement paging that:

1. Orders by TimeStamp
2. Starts out using a suggested pageSize (say 4), but will automatically adjust to include additional records matching on TimeStamp. In other words, if 1/1/2013 01:00 is included for one ParentId, the suggested pageSize will be overridden and all records for hour 01:00 will be included for all ParentId's. It's almost like the TOP WITH TIES option.

So running this query with pageSize of 4 would return 6 records. There are 3 hour 00:00 and 1 hour 01:00 by default, but because there are more hour 01:00's, the pageSize would be overridden to return all hour 00:00 and 01:00.

Here's what I have so far, and I think I'm close as it works for the first iteration, but sequent queries for the next pageSize+ rows doesn't work.

WITH CTE AS
(
    SELECT ParentId, [TimeStamp], Value,
    RANK() OVER(ORDER BY [TimeStamp]) AS rnk,
    ROW_NUMBER() OVER(ORDER BY [TimeStamp]) AS rownum
    FROM @Temp
)

SELECT *
FROM CTE
WHERE (rownum BETWEEN 1 AND 4) OR (rnk BETWEEN 1 AND 4)
ORDER BY TimeStamp, ParentId

The ROW_NUMBER ensures the minimum pageSize is met, but the RANK will include additional ties.

Answer 1

declare @Temp as Table ( ParentId Int, [TimeStamp] DateTime, [Value] Int );
insert into @Temp ( ParentId, [TimeStamp], [Value] ) values
 (1, '1/1/2013 00:00', 6),
 (1, '1/1/2013 01:00', 7),
 (1, '1/1/2013 02:00', 8),
 (2, '1/1/2013 00:00', 6),
 (2, '1/1/2013 01:00', 7),
 (2, '1/1/2013 02:00', 8),
 (3, '1/1/2013 00:00', 6),
 (3, '1/1/2013 01:00', 7),
 (3, '1/1/2013 02:00', 8);

declare @PageSize as Int = 4;
declare @Page as Int = 1;

with Alpha as (
    select ParentId, [TimeStamp], Value,
        Rank() over ( order by [TimeStamp] ) as Rnk,
        Row_Number() over ( order by [TimeStamp] ) as RowNum
    from @Temp ),
    Beta as (
    select Min( Rnk ) as MinRnk, Max( Rnk ) as MaxRnk
        from Alpha
        where ( @Page - 1 ) * @PageSize < RowNum and RowNum <= @Page * @PageSize )
    select A.*
        from Alpha as A inner join
            Beta as B on B.MinRnk <= A.Rnk and A.Rnk <= B.MaxRnk
        order by [TimeStamp], ParentId;

EDIT: An alternative query that assigns page numbers as it goes, so that next/previous page can be implemented without overlapping rows:

with Alpha as (
    select ParentId, [TimeStamp], Value,
        Rank() over ( order by [TimeStamp] ) as Rnk,
        Row_Number() over ( order by [TimeStamp] ) as RowNum
    from @Temp ),
    Beta as (
    select ParentId, [TimeStamp], Value, Rnk, RowNum, 1 as Page, 1 as PageRow
        from Alpha
        where RowNum = 1
    union all
    select A.ParentId, A.[TimeStamp], A.Value, A.Rnk, A.RowNum,
        case when B.PageRow >= @PageSize and A.TimeStamp <> B.TimeStamp then B.Page + 1 else B.Page end,
        case when B.PageRow >= @PageSize and A.TimeStamp <> B.TimeStamp then 1 else B.PageRow + 1 end
        from Alpha as A inner join
            Beta as B on B.RowNum + 1 = A.RowNum
     )
    select * from Beta
        option ( MaxRecursion 0 )

Note that recursive CTEs often scale poorly.