I would do it by converting it to a real date, subtracting a month, then turning it back to a string, as attached. You could also do an case statement which may be easier.
case [month] when "January" then"December"
month.twbx.zip 32.0 KB
Thanks for your help.
dateadd('month',-1,[Change to a real date]) worked for me...
I only dont get what you mean with Remove date to stop any issues :datename('month',[Move a month])
Can you make it clear to me?
Sure, you started with a string this is now a date - the month is right but I arbitrarily chose the year 2000. Now your original january is actually Dec 1999. I just feel that leaving it as a real date could be confusing down the line if someone thought the year had any significance - for example if you drag the pill over, you then have to jump through hoops to get it to displace just the month, not the year/month year, etc.
Now if you have a real, real, date you could use in your source, I would just use the dateadd formula