Find conflicted date intervals using SQL

Question

Suppose I have following table in Sql Server 2008:

ItemId StartDate   EndDate
1      NULL        2011-01-15
2      2011-01-16  2011-01-25
3      2011-01-26           


        

Answer 1

This will give you the rows that are incorrect.

Added ROW_NUMBER() as I didnt know if all entries where in order.

-- Testdata
declare @date datetime = '2011-01-17'

;with yourTable(itemID, startDate, endDate)
as
(
    SELECT  1,  NULL, @date
    UNION ALL
    SELECT  2,  dateadd(day, -1, @date),    DATEADD(day, 10, @date)
    UNION ALL
    SELECT  3,  DATEADD(day, 60, @date),    NULL
)

-- End testdata

,tmp
as
(
    select  *
            ,ROW_NUMBER() OVER(order by startDate) as rowno 
    from    yourTable
)

select  *
from    tmp t1
left join   tmp t2
    on t1.rowno = t2.rowno - 1
where   t1.endDate > t2.startDate

EDIT: As for the updated question:

Just add a PARTITION BY clause to the ROW_NUMBER() query and alter the join.

-- Testdata
declare @date datetime = '2011-01-17'

;with yourTable(itemID, startDate, endDate, intervalID)
as
(
    SELECT  1,  NULL, @date, 1
    UNION ALL
    SELECT  2,  dateadd(day, 1, @date), DATEADD(day, 10, @date),1
    UNION ALL
    SELECT  3,  DATEADD(day, 60, @date),    NULL,   1
    UNION ALL
    SELECT  4,  NULL, @date, 2
    UNION ALL
    SELECT  5,  dateadd(day, -1, @date),    DATEADD(day, 10, @date),2
    UNION ALL
    SELECT  6,  DATEADD(day, 60, @date),    NULL,   2
)

-- End testdata

,tmp
as
(
    select  *
            ,ROW_NUMBER() OVER(partition by intervalID order by startDate) as rowno 
    from    yourTable
)

select  *
from    tmp t1
left join   tmp t2
    on t1.rowno = t2.rowno - 1
    and t1.intervalID = t2.intervalID
where   t1.endDate > t2.startDate