SQL Query Help - Negative reporting - sql

Question

Perhaps somebody can help with Ideas or a Solution. A User asked me for a negative report. We have a table with tickets each ticket has a ticket number which would be easy to select but the user wants a list of missing tickets between the first and last ticket in the system.
E.g. Select TicketNr from Ticket order by TicketNr
Result
1,
2,
4,
7,
11
But we actually want the result 3,5,6,8,9,10
CREATE TABLE [dbo].[Ticket](
[pknTicketId] [int] IDENTITY(1,1) NOT NULL,
[TicketNr] [int] NULL
) ON [PRIMARY]
GO
SQL Server 2016 - TSQL
Any ideas ?
So a bit more information is need all solution thus far works on small table. Our production database has over 4 million tickets. Hence why we need to find the missing ones.

Answer 1

First get the minimum and maximum, then generate all posible ticket numbers and finally select the ones that are missing.
;WITH FirstAndLast AS
(
SELECT
MinTicketNr = MIN(T.TicketNr),
MaxTicketNr = MAX(T.TicketNr)
FROM
Ticket AS T
),
AllTickets AS
(
SELECT
TicketNr = MinTicketNr,
MaxTicketNr = T.MaxTicketNr
FROM
FirstAndLast AS T
UNION ALL
SELECT
TicketNr = A.TicketNr + 1,
MaxTicketNr = A.MaxTicketNr
FROM
AllTickets AS A
WHERE
A.TicketNr + 1 <= A.MaxTicketNr
)
SELECT
A.TicketNr
FROM
AllTickets AS A
WHERE
NOT EXISTS (
SELECT
'missing ticket'
FROM
Ticket AS T
WHERE
A.TicketNr = T.TicketNr)
ORDER BY
A.TicketNr
OPTION
(MAXRECURSION 32000)

Answer 2

If you can accept the results in a different format, the following will do what you want:
select TicketNr + 1 as first_missing,
next_TicketNr - 1 as last_missing,
(next_TicketNr - TicketNr - 1) as num_missing
from (select t.*, lead(TicketNr) over (order by TicketNr) as next_TicketNr
from Ticket t
) t
where next_TicketNr <> TicketNr + 1;
This shows each sequence of missing ticket numbers on a single row, rather than a separate row for each of them.
If you do use a recursive CTE, I would recommend doing it only for the missing tickets:
with cte as (
select (TicketNr + 1) as missing_TicketNr
from (select t.*, lead(TicketNr) over (order by TicketNr) as next_ticketNr
from tickets t
) t
where next_TicketNr <> TicketNr + 1
union all
select missing_TicketNr + 1
from cte
where not exists (select 1 from tickets t2 where t2.TicketNr = cte.missing_TicketNr + 1)
)
select *
from cte;
This version starts with the list of missing ticket numbers. It then adds a new one, as the numbers are not found.

Answer 3

One method is to use recursive cte to find the missing ticket numbers :
with missing as (
select min(TicketNr) as mnt, max(TicketNr) as mxt
from ticket t
union all
select mnt+1, mxt
from missing m
where mnt < mxt
)
select m.*
from missing m
where not exists (select 1 from tickets t where t.TicketNr = m.mnt);

Answer 4

This should do the trick: SQL Fiddle
declare #ticketsTable table (ticketNo int not null)
insert #ticketsTable (ticketNo) values (1),(2),(4),(7),(11)
;with cte1(ticketNo, isMissing, sequenceNo) AS
(
select ticketNo
, 0
, row_number() over (order by ticketNo)
from #ticketsTable
)
, cte2(ticketNo, isMissing, sequenceNo) AS
(
select ticketNo, isMissing, sequenceNo
from cte1
union all
select a.ticketNo + 1
, 1
, a.sequenceNo
from cte2 a
inner join cte1 b
on b.sequenceNo = a.sequenceNo + 1
and b.ticketNo != a.ticketNo + 1
)
select *
from cte2
where isMissing = 1
order by ticketNo
It works by collecting all of the existing tickets, marking them as existing, and assigning each a consecutive number giving their order in the original list.
We can then see the gaps in the list by finding any spots where the consecutive order number shows the next record, but the ticket numbers are not consecutive.
Finally, we recursively fill in the gaps; working from the start of a gap and adding new records until that gap's consecutive numbers no longer has a gap between the related ticket numbers.

Answer 5

I think this one give you easiest solution
with cte as(
select max(TicketNr) maxnum,min(TicketNr) minnum from Ticket )
select a.number FROM master..spt_values a,cte
WHERE Type = 'P' and number < cte.maxnum and number > cte.minno
except
select TicketNr FROM Ticket

Answer 6

So After looking at all the solutions
I went with creating a temp table with a full range of number from Starting to Ending ticket and then select from the Temp table where the ticket number not in the ticket table.
The reason being I kept running in MAXRECURSION problems.