Comments on: SQL Puzzle: SQL Advance Query – Count the total number of missing Numbers

By: Suraj MU

Suraj MU — Sat, 25 Apr 2020 05:56:03 +0000

SELECT (MAX(number)-MIN(number)+1) – COUNT(number)
FROM tbl_ranges

By: vinay

vinay — Tue, 25 Dec 2018 17:24:49 +0000

SELECT ((SELECT max(number) from tbl_ranges)- (SELECT count(number) from tbl_ranges))

By: Ankush

Ankush — Fri, 14 Sep 2018 08:27:00 +0000

Select max(diff)
from
(Select num, rownum, num-rownum as diff from table)

By: VINUTNA

VINUTNA — Tue, 22 May 2018 12:01:45 +0000

with cte as
(
select number, lead(number)over (order by number) as lead_values from tbl_Ranges
),
cte1 as
(
select (lead_values – number)-1 as required from cte
)
select sum(required) from cte1
where required >= 1

By: aprkturk

aprkturk — Mon, 15 Jan 2018 11:27:00 +0000

If it starts with 1 it is ok otherwise no.

By: Dinesh IS

Dinesh IS — Thu, 30 Nov 2017 07:05:03 +0000

Declare @MaxNumber As Int
Select @MaxNumber=Max(Number)
From TBL_Ranges
;
WITH CTE
As
(Select 1 As SLNo
Union All
Select SLNo+1
From CTE
Where SLNo<@MaxNumber)
Select Count(SLNo) As NoOfNumber From CTE
Where SLNo Not In(Select Number From TBL_Ranges)

By: Anvesh Patel

Anvesh Patel — Mon, 27 Nov 2017 11:58:25 +0000

In reply to Harikrushna V. Adiecha. Not sure about any tool, but checking query execution plan we can estimate the complexity of any query.

By: Harikrushna V. Adiecha

Harikrushna V. Adiecha — Mon, 27 Nov 2017 08:38:00 +0000

I solve this in mysql database. please check, i tried, and it’s working fine.

Solution #1:

SELECT SUM(p.diff) as TotalMissingNumbers from
(
SELECT t.Number,
t.Number – @last – 1 AS diff,
@last := t.Number AS last
FROM tbl_ranges t,
(SELECT @last := 0) r
) as p

I found one more solution, which is even simpler and straight forward

Solution #2:

SELECT MAX(Number) – COUNT(Number) as TotalMissingNumbers FROM tbl_ranges

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Apart from this, I wish to know how can we calculate complexity of the query we wrote, if you know any tool or any technique to get such calculations then please let me know.

I’m very curious to know such things.