SQL if breaking number pattern, mark record? - sql

Question

I have the following query:
SELECT AccountNumber, RptPeriod
FROM dbo.Report
ORDER BY AccountNumber, RptPeriod.
I get the following results:
123 200801
123 200802
123 200803
234 200801
344 200801
344 200803
I need to mark the record where the rptperiod doesnt flow concurrently for the account. For example 344 200803 would have an X next to it since it goes from 200801 to 200803.
This is for about 19321 rows and I want it on a company basis so between different companies I dont care what the numbers are, I just want the same company to show where there is breaks in the number pattern.
Any Ideas??
Thanks!

Answer 1

OK, this is kind of ugly (double join + anti-join) but it gets the work done, AND is pure portable SQL:
SELECT *
FROM dbo.Report R1
, dbo.Report R2
WHERE R1.AccountNumber = R2.AccountNumber
AND R2.RptPeriod - R1.RptPeriod > 1
-- subsequent NOT EXISTS ensures that R1,R2 rows found are "next to each other",
-- e.g. no row exists between them in the ordering above
AND NOT EXISTS
(SELECT 1 FROM dbo.Report R3
WHERE R1.AccountNumber = R3.AccountNumber
AND R2.AccountNumber = R3.AccountNumber
AND R1.RptPeriod < R3.RptPeriod
AND R3.RptPeriod < R2.RptPeriod
)

Answer 2

Something like this should do it:
-- cte lists all items by AccountNumber and RptPeriod, assigning an ascending integer
-- to each RptPeriod and restarting at 1 for each new AccountNumber
;WITH cte (AccountNumber, RptPeriod, Ranking)
as (select
AccountNumber
,RptPeriod
,row_number() over (partition by AccountNumber order by AccountNumber, RptPeriod) Ranking
from dbo.Report)
-- and then we join each row with each preceding row based on that "Ranking" number
select
This.AccountNumber
,This.RptPeriod
,case
when Prior.RptPeriod is null then '' -- Catches the first row in a set
when Prior.RptPeriod = This.RptPeriod - 1 then '' -- Preceding row's RptPeriod is one less that This row's RptPeriod
else 'x' -- -- Preceding row's RptPeriod is not less that This row's RptPeriod
end UhOh
from cte This
left outer join cte Prior
on Prior.AccountNumber = This.AccountNumber
and Prior.Ranking = This.Ranking - 1
(Edited to add comments)

Answer 3

WITH T
AS (SELECT *,
/*Each island of contiguous data will have
a unique AccountNumber,Grp combination*/
RptPeriod - ROW_NUMBER() OVER (PARTITION BY AccountNumber
ORDER BY RptPeriod ) Grp,
/*RowNumber will be used to identify first record
per company, this should not be given an 'X'. */
ROW_NUMBER() OVER (PARTITION BY AccountNumber
ORDER BY RptPeriod ) AS RN
FROM Report)
SELECT AccountNumber,
RptPeriod,
/*Check whether first in group but not first over all*/
CASE
WHEN ROW_NUMBER() OVER (PARTITION BY AccountNumber, Grp
ORDER BY RptPeriod) = 1
AND RN > 1 THEN 'X'
END AS Flag
FROM T

Answer 4

SELECT *
FROM report r
LEFT JOIN report r2
ON r.accountnumber = r.accountnumber
AND {r2.rptperiod is one day after r.rptPeriod}
JOIN report r3
ON r3.accountNumber = r.accountNumber
AND r3.rptperiod > r1.rptPeriod
WHERE r2.rptPeriod IS NULL
AND r3 IS NOT NULL
I'm not sure of sql servers date logic syntax, but hopefully you get the idea. r will be all the records where the next rptPeriod is NULL (r2) and there exists at least one greater rptPeriod (r3). The query isn't super straight forward I guess, but if you have an index on the two columns, it'll probably be the most efficent way to get your data.

Answer 5

Basically, you number rows within every account, then, using the row numbers, compare the RptPeriod values for the neighbouring rows.
It is assumed here that RptPeriod is the year and month encoded, for which case the year transition check has been added.
;WITH Report_sorted AS (
SELECT
AccountNumber,
RptPeriod,
rownum = ROW_NUMBER() OVER (PARTITION BY AccountNumber ORDER BY RptPeriod)
FROM dbo.Report
)
SELECT
AccountNumber,
RptPeriod,
CASE ISNULL(CASE WHEN r1.RptPeriod / 100 < r2.RptPeriod / 100 THEN 12 ELSE 0 END
+ r1.RptPeriod - r2.RptPeriod, 1) AS Chk
WHEN 1 THEN ''
ELSE 'X'
END
FROM Report_sorted r1
LEFT JOIN Report_sorted r2
ON r1.AccountNumber = r2.AccountNumber AND r1.rownum = r2.rownum + 1
It could be complicated further with an additional check for gaps spanning a year and more, if you need that.