How do I select the most frequent value for a specific month and display this value as well as the amount of times it occurs? - sql

Question

I am struggling with a TSQL query and I'm all out of googling, so naturally I figured I might as well ask on SO.
Please keep in mind that I just began trying to learn SQL a few weeks back and I'm not really sure what rules there are and how you can and can not write your queries / sub-queries.
This is what I have so far:
Edit: Updated with DDL that should help create an example, also commented out unnecessary "Client"-column.
CREATE TABLE NumberTable
(
Number varchar(20),
Date date
);
INSERT INTO NumberTable (Number, Date)
VALUES
('55512345', '2015-01-01'),
('55512345', '2015-01-01'),
('55512345', '2015-01-01'),
('55545678', '2015-01-01'),
('55512345', '2015-02-01'),
('55523456', '2015-02-01'),
('55523456', '2015-02-01'),
('55534567', '2015-03-01'),
('55534567', '2015-03-01'),
('55534567', '2015-03-01'),
('55534567', '2015-03-01'),
('55545678', '2015-03-01'),
('55545678', '2015-04-01')
DECLARE
--#ClientNr AS int,
#FromDate AS date,
#ToDate AS date
--SET #ClientNr = 11111
SET #FromDate = '2015-01-01'
SET #ToDate = DATEADD(yy, 1, #FromDate)
SELECT
YEAR(Date) AS [Year],
MONTH(Date) AS [Month],
COUNT(Number) AS [Total Count]
FROM
NumberTable
WHERE
--Client = #ClientNr
Date BETWEEN #FromDate AND #ToDate
AND Number IS NOT NULL
AND Number NOT IN ('888', '144')
GROUP BY MONTH(Date), YEAR(Date)
ORDER BY [Year], [Month]
With this I am getting the Year, Month and Total Count.
I'm happy with only getting the top 1 most called number and count each month, but showing top 5 is preferable.
Heres an example of how I would like the table to look in the end (having the months formatted as JAN, FEB etc instead of numbers is not really important, but would be a nice bonus):
╔══════╦═══════╦═════════════╦═══════════╦══════════╦═══════════╦══════════╗
║ Year ║ Month ║ Total Count ║ #1 Called ║ #1 Count ║ #2 Called ║ #2 Count ║
╠══════╬═══════╬═════════════╬═══════════╬══════════╬═══════════╬══════════╣
║ 2016 ║ JAN ║ 80431 ║ 555-12345 ║ 45442 ║ 555-94564 ║ 17866 ║
╚══════╩═══════╩═════════════╩═══════════╩══════════╩═══════════╩══════════╝
I was told this was "easily" done with a sub-query, but I'm not so sure...

Answer 1

Interesting one this, I believe you can do it with a CTE and PIVOT but this is off the top of my head... This may not work verbatim
WITH Rollup_CTE
AS
(
SELECT Client,MONTH(Date) as Month, YEAR(Date) as Year, Number, Count(0) as Calls, ROW_NUMBER() OVER (PARTITION BY Client,MONTH(Date) as SqNo, YEAR(Date), Number ORDER BY COUNT(0) DESC)
from NumberTable
WHERE Number IS NOT NULL AND Number NOT IN ('888', '144')
GROUP BY Client,MONTH(Date), YEAR(Date), Number
)
SELECT * FROM Rollup_CTE Where SqNo <=5
You may then be able to pivot the data as you wish using PIVOT

Answer 2

artm's query corrected (PARTITION) and the last step (pivoting) simplified.
with data AS
(select '2016-01-01' as called, '111' as number
union all select '2016-01-01', '111'
union all select '2016-01-01', '111'
union all select '2016-01-01', '222'
union all select '2016-01-01', '222'
union all select '2016-01-05', '111'
union all select '2016-01-05', '222'
union all select '2016-01-05', '222')
, ordered AS (
select called
, number
, count(*) cnt
, ROW_NUMBER() OVER (PARTITION BY called ORDER BY COUNT(*) DESC) rnk
from data
group by called, number)
select called, total = sum(cnt)
, n1= max(case rnk when 1 then number end)
, cnt1=max(case rnk when 1 then cnt end)
, n2= max(case rnk when 2 then number end)
, cnt2=max(case rnk when 2 then cnt end)
from ordered
group by called
EDIT Using setup provided by OP
WITH ordered AS(
-- compute order
SELECT
[Year] = YEAR(Date)
, [Month] = MONTH(Date)
, number
, COUNT(*) cnt
, ROW_NUMBER() OVER (PARTITION BY YEAR(Date), MONTH(Date) ORDER BY COUNT(*) DESC) rnk
FROM NumberTable
WHERE Date BETWEEN #FromDate AND #ToDate
AND Number IS NOT NULL
AND Number NOT IN ('888', '144')
GROUP BY YEAR(Date), MONTH(Date), number
)
-- pivot by order
SELECT [Year], [Month]
, total = sum(cnt)
, n1 = MAX(case rnk when 1 then number end)
, cnt1 = MAX(case rnk when 1 then cnt end)
, n2 = MAX(case rnk when 2 then number end)
, cnt2 = MAX(case rnk when 2 then cnt end)
-- n3, cnt3, ....
FROM ordered
GROUP BY [Year], [Month];

Answer 3

This query help you:
IF OBJECT_ID('tempdb..#Test','U') IS NOT NULL DROP TABLE #Test;
CREATE TABLE #Test(Number INT NOT NULL)
INSERT INTO #Test(Number)
VALUES(1),(2),(3),(1)
SELECT TOP 1 WITH TIES
Number
FROM (
SELECT DISTINCT
Number
, COUNT(*) OVER(PARTITION BY Number) AS cnt
FROM #Test) AS T
ORDER BY cnt DESC
I have used TOP 1 WITH TIES for case when max count exists for several values.

Answer 4

Try this, doesn't have to be CTE but I used it to populate data, you can extend it to include 3rd, 4th etc.
;with data AS
(select '2016-01-01' as called, '111' as number
union all select '2016-01-01', '111'
union all select '2016-01-01', '111'
union all select '2016-01-01', '222'
union all select '2016-01-01', '222')
, ordered AS (
select called
, number
, count(*) cnt
, ROW_NUMBER() OVER (ORDER BY COUNT(*) DESC) rnk
from data
group by called, number)
SELECT distinct *
FROM (SELECT DATENAME(month, called) mnth FROM ordered) AS mnth,
(SELECT number MostCalledNumber FROM ordered WHERE rnk = 1) AS MostCalledNumber,
(SELECT cnt MostCalledTimes FROM ordered WHERE rnk = 1) AS MostCalledTimes,
(SELECT number SecondMostCalledNumber FROM ordered WHERE rnk = 2) AS SecondMostCalledNumber,
(SELECT cnt SecondMostCalledTimes FROM ordered WHERE rnk = 2) AS SecondMostCalledTimes