COUNT monthly sales for every year - sql-server

Question

I need to check monthly sales (count not sum) by area for long ranges of dates (5+ years), something like an Excel pivot table, currently I'm working it on Pandas but nobody here works with it so I'm trying to generate a view or a stored procedure in SQLServer for anyone who requires it. In this table sales are stored associated to an area and which product was.
I'm able to list and group AREA, SALES, MONTH AND YEAR, but as I mentioned, it would be easier to read if months or years where vertically aligned (there is about 100k records yearly and Excel lags at that point).
CREATE TABLE SALESHS
(
IDAREA INT,
DATEREG [NVARCHAR](50) NOT NULL,
IDPROD [NVARCHAR](50) NOT NULL
);
GO
-- Insert rows into table 'SALESHS'
INSERT INTO SALESHS
(
IDAREA, DATEREG, IDPROD
)
VALUES
(
1, '12/03/2019', 'xplpc'
),
(
1, '15/03/2019', 'ndtlctm'
),
(
2, '12/04/2019', 'wntd'
)
GO
SELECT IDAREA,
COUNT(IDAREA) AS CANT,
DATEREG, --DATE AS DD/MM/YYYY
DATEPART(MM,CAST(DATEREG AS DATETIME)) AS MONTH,
DATEPART(YYYY,CAST(DATEREG AS DATETIME)) AS YEAR,
FROM saleshs
WHERE DATEREG > 201712
GROUP BY DATEREG , idarea
ORDER BY DATEREG
Which returns this:
IDAREA AMOUNT MONTH YEAR PER_PRO
----------------------------------------
1 2 03 2019 201904
2 1 04 2019 201904
Expected results:
IDAREA JAN2019 FEB2019 MAR2019 APR2019
--------------------------------------
1 0 0 2 0
2 0 0 0 1
I know the basics of SQL and I don't expect a full answer either, but anything that could help me build this view it's appreciated. I've tried PIVOT also but I can't count, distinct and sum in the same query.

Answer 1

You can try Conditional Aggregation
SELECT IDAREA,
SUM( CASE WHEN YEAR(CAST(DATEREG AS DATETIME))= 2019 AND
MONTH(CAST(DATEREG AS DATETIME))=1 THEN
1
ELSE
0
END) JAN2019,
SUM( CASE WHEN YEAR(CAST(DATEREG AS DATETIME))= 2019 AND
MONTH(CAST(DATEREG AS DATETIME))=2 THEN
1
ELSE
0
END) FEB2019,
SUM( CASE WHEN YEAR(CAST(DATEREG AS DATETIME))= 2019 AND
MONTH(CAST(DATEREG AS DATETIME))=3 THEN
1
ELSE
0
END) MAR2019,
SUM( CASE WHEN YEAR(CAST(DATEREG AS DATETIME))= 2019 AND
MONTH(CAST(DATEREG AS DATETIME))=4 THEN
1
ELSE
0
END) APR2019
FROM saleshs
WHERE YEAR(CAST(DATEREG AS DATETIME))> 2017
GROUP BY IDAREA
ORDER BY IDAREA
Demo

Answer 2

--Build the column names for Pivot using dynamic SQL
DECLARE #YourChoice date
set #YourChoice = '2017/12/13' --change here to what date you want the earliest
declare #count int = 0
declare #columnstr varchar(max)
declare #columnpivot varchar(max)
declare #onecolumnname varchar(20)
set #columnstr = ''
set #columnpivot = ''
set #onecolumnname = ''
while #count <= DATEDIFF(MONTH,#YourChoice,GETDATE())
begin
set #onecolumnname = concat(cast(datename(month,dateadd(month,#count,#YourChoice)) as varchar(50)),cast(year(dateadd(month,#count,#YourChoice)) as varchar(10)))
set #columnstr = #columnstr + 'coalesce([' + #onecolumnname+ '],0) as '+#onecolumnname+', '
set #columnpivot = #columnpivot + '['+#onecolumnname+'], '
set #count = #count + 1
end
set #columnstr = left(#columnstr,len(#columnstr)-1)
set #columnpivot = '('+left(#columnpivot,len(#columnpivot)-1)+')'
--Pivot time!
declare #str varchar(max)
set #str =
'select IDAREA,' + #columnstr +' from (
select count(s.idarea) as amount,IDAREA,columnname from (
select *,datename(month,cast(substring(datereg,7,4)+''-''+substring(datereg,4,2)+''-''+substring(datereg,1,2) as datetime)) + SUBSTRING(datereg,7,4) as columnname
from SALESHS )s
group by IDAREA,columnname)s1
pivot
(
max(s1.amount)
for s1.columnname in '+#columnpivot+'
) p'
exec (#str)
Test Result 1 ('2017/12/13'):
DB<>Fiddle
Test Result 2 ('2018/12/14'):
DB<>Fiddle

Answer 3

I have created a Dynamic SQL to solve this particular issue. Query can be adjusted on which YEAR to display in the result and which Column to count in the PIVOT Section of the query. Date format in the i have used is below query MM/DD/YYYY.
You can run the code HERE
Below is the SQL Query.
CREATE TABLE SALESHS
( IDAREA INT,
DATEREG date NOT NULL,
IDPROD [NVARCHAR](50) NOT NULL
);
/* Insert rows into table 'SALESHS' */
INSERT INTO SALESHS
( IDAREA, DATEREG, IDPROD)
VALUES
( 1, '03/12/2019', 'xplpc'),
( 1, '03/15/2019', 'ndtlctm'),
( 2, '04/12/2019', 'wntd')
/* Create Calendar Table to capture all the dates for first day of month from start Date to end date */
CREATE TABLE Calendar
(
[CalendarDate] DATE
,[MonthName] AS FORMAT(CONVERT(DATE, DATEADD(m, DATEDIFF(m, 0, CalendarDate), 0)), 'MMM-yyyy')
,[MonthNo] AS FORMAT(CalendarDate,'MM')
,[Year] AS FORMAT(CalendarDate,'yyyy')
,DateKey AS CONCAT(FORMAT(CalendarDate,'yyyy'), FORMAT(CalendarDate,'MM'))
)
DECLARE #Date DATE, #StartDate DATE, #EndDate DATE
SET #Date = '01/01/2012'
SET #StartDate = CONVERT(DATE, DATEADD(m, DATEDIFF(m, 0, #Date), 0)) /* Set Start date to first day of the month for given date */
SET #EndDate = '04/01/2019'
WHILE #StartDate <= #EndDate
BEGIN
INSERT INTO Calendar (CalendarDate)
SELECT #StartDate
SET #StartDate = DATEADD(m, 1, #StartDate)
END
/* Variable to hold unique Months to be used in PIVOT clause */
DECLARE #UniqueMonthsToPivot NVARCHAR(MAX) = N''
/* Extract unique Month names with pivot formattings */
SELECT #UniqueMonthsToPivot = #UniqueMonthsToPivot + ', [' + COALESCE(MonthName, '') + ']'
FROM (SELECT DISTINCT MonthName FROM Calendar) DT
/* Remove first comma and space */
SELECT #UniqueMonthsToPivot = LTRIM(STUFF(#UniqueMonthsToPivot, 1, 1, ''))
/* Variable to hold pivot column names with alias to be used in SELECT Clause */
DECLARE #PivotMonthsToSelect NVARCHAR(MAX) = N''
/* Generate column names list for SELECT list with SUM Function and NULL handling.
YEAR in the where condition can be adjust to select and show only certain year or month in Select list.
Order by CalendarDate is important to define the sequence of columns in the result */
SELECT #PivotMonthsToSelect = #PivotMonthsToSelect + ', SUM(ISNULL([' + COALESCE(MonthName, '') + '], 0)) AS [' + MonthName + ']'
FROM Calendar WHERE Year >= 2012
Order by CalendarDate
/* Variable to hold t-sql query */
DECLARE #SQLStatement NVARCHAR(MAX) = N''
/* Generate dynamic PIVOT query here */
SET #SQLStatement =
N'SELECT IDAREA'
+ #PivotMonthsToSelect +
'FROM (
SELECT *
,CASE WHEN IDAREA IS NULL THEN 0 ELSE 1 END AS IDAREA_Dup
FROM Calendar C
LEFT JOIN SALESHS S ON C.CalendarDate = CONVERT(DATE, DATEADD(m, DATEDIFF(m, 0, DATEREG), 0))
) AA
PIVOT
( SUM(IDAREA_Dup)
FOR MonthName IN ('+ #UniqueMonthsToPivot +')
) P
WHERE IDAREA IS NOT NULL
GROUP BY IDAREA
'
/* Check the generated dynamic t-sql PIVOT query below */
--PRINT (#SQLStatement)
/* Execute the generated dynamic t-sql PIVOT query below */
EXEC (#SQLStatement)