I'm not really sure to understand what your question is about as you talk about dimension first and then about a prompt on a column ....
If you have a "Year" column which is used in a prompt and instead of YYYY you want to display YY-YY (so 2017 => 20-17 etc.) then it will be a string, and you can simple cast the year as string and then use substring to split the first 2 characters , concatenate the '-' and add the last 2 characters.
But it will not be "Year" anymore, it will be the formula you wrote as string. So all depends what you want to do with it.
Not exactly sure what you mean but if you generally want years to display as YY-YY then the best way to do this is to add a column containing this value to your time dimension.
Beware of putting function logic on time measures that you then use as filters.
This will have a very real impact on performance.
Better is either to have the values populated in the format that you want in the data warehouse, or if that is not possible then tell the end user population to live with it, the trade off on speed is not worth the cosmetic appearance!
Thank you all, we were able to efficiently convince our customers this unnecessary cosmetic change will lower performance and was able to keep it in the same format as a year should!
WTH just happened? A customer listened to community advice? Lollipops for everyone!
LOL, I was thinking the same. A bold move but worked out due to the technical advice provided on this thread regarding unnecessary changes! Cheers to all !