Sorting by Year/Month - Working 50% of the time

[Anonymous]

Much like (seemingly) everyone, I am trying to sort my data by Year/Month. I managed to get a working solution that I can use with 1 set of data (formatted a certain way), but when I use another, almost identical, set of data I get an error.

What works:

1. [Created Date] is a column of dates that, by default, is "24-01-19 12:08:00". In Power Query Editor I set this to type Data and then "Date Only", giving me "24/01/2019".
   
   
2. Back in the Desktop tool, I created a new (calculated?) column with this: CreateDateSort = FORMAT('ICT Tickets - Last 6 Months'[Created Date].[Date],"YYYY mm"). By default this was a TEXT data type and displayed the columns like this:
   
   
   
3. I set this to data type Date and I got this output (which is the desired output):
   

What doesn't work

1. Similarly, I have [Closed Date] which was treated exactly the same way: raw data formatted and extracted to only show the Date.
   
   
2. New column created ClosedDateSort = FORMAT('ICT Tickets - Last 6 Months'[Closed Date].[Date],"YYYY mm"), formatted to type Text:
   
   
   
3. I set this to data type Date and then it breaks. I've tried different Format options and all yield the same:
   

Is there something really obvious I am missing?

[Anonymous · Accepted solution]

Whenever I need to group data within a single month, I just create a "Month" column that uses the StartOfMonth function on whatever Date column i care about (Query editor, add column is the easiest way).  I then format the column to show the date as "MMMM yyyy".

[Anonymous]

Legend! That did it. Thanks so much.