How to get all months between two dates in sql with data - sql

Question

Please suggest a method where in we could retrieve name of all months in between two dates.
The months may or may not contain data, but as the need is to display monthly trend, we are required to fetch all months in between two date ranges with or without data.
The Output will be like:
Jan | Feb | Mar
----------------------
Data | Data| Data

Answer 1

If you use SQL Server, you can use the MONTH() or DATEPART() function to extract the month from a date. For example, the following statement returns the current month in SQL Server: SELECT MONTH(CURRENT_TIMESTAMP); SELECT DATEPART(month, CURRENT_TIMESTAMP);
You could then do a GROUP BY to determine how many events occur per month

Answer 2

In general "dynamic columns" are much harder to achieve than "dynamic rows" so output that looks like the first of the tables below will be easier to achieve than output that looks like the second.
Easier
Month | Data
-------------
Jan | Data
Feb | Data
Mar | Data
Harder
Jan | Feb | Mar
----------------------
Data | Data | Data
In general, the best approach is to have your SQL queries return data in the first type of structure and then if required transform this to the second type in your "presentation layer", which might be in Excel, PowerBI, SSRS, or on a website, for example.
If you have months where there might be no data to be returned, you need some means of generating the months and then outer joining this to the data. Obviously in general, at least behind the scenes you'll want to be including years in your data in addition months as otherwise all the data from Jan 2020 will be grouped together with that from Jan 2021, which is probably not what you want.
Here is a SQL-Server-friendly snippet which will output all the months (and years) between two dates. At the time of writing, you haven't specified a DBMS, so if you aren't on SQL Server, this may not work for you.
DECLARE #datefrom DATE = '2020-06-01'
DECLARE #dateto DATE = '2021-03-01';
WITH cte AS
(
SELECT #datefrom as MyDate
UNION ALL
SELECT DATEADD(month,1,MyDate)
FROM cte
WHERE DATEADD(month,1,MyDate)<=#dateto
)
SELECT
YEAR(cte.MyDate) CalendarYear,
MONTH(cte.MyDate) CalendarMonth,
DATENAME(month, cte.MyDate) as MonthNameFull,
CONVERT(char(3),cte.MyDate,0) as MonthName3Char
FROM
cte
ORDER BY
Year(cte.MyDate),
Month(cte.MyDate)
The final SELECT query could be OUTER JOINed to your actual data to give you your desired results. Pivoting should then be done in the presentation layer.
An alternative to the cte would be to use a "numbers table" and use that to add a number of months to the start date and limit the output to where the result of adding that number of months is between the two provided dates.