Creating a new colunm with max values of another column for each month

[#1]

Hello community, 

I would like to create an extra colunm as in the example below. The result is the max of the volume of data per month. I have tried to do it with "group by" of the :month column and then use the "max()" function from the formula option but no sucess. Anyone has an idea to create this extra colunm without going to summary and merge. thanks!! 

[#2]

Group By and Maximum quick formula should work

If this doesn't work, are your months really string months or are they formatted dates (in which case you might have to perform extra steps)?

[#3]

Bug thanks Jarmo!! Two reasons why it did not work for me: Indeed, the date format (big kudos for detecting it) and the fact that "group by" was selected on the wrong column.

Side question: When formula is active, we have a big cross appearing close to the column name. What about "group by'? Any hint if a column was selected as "group by"? I feel it's critical to let the user know that this is on and on which column.  thx!! _Jm

[#4]

Easiest way is to view the formula but you could add Notes property yourself to such columns. If you wish to have something new in JMP, make a new post to JMP Wish List

[#5 · Accepted solution]

The Group By column is added to the column name:

The current GroupBy columns are listed at the bottom of the New Formula Column Menu:

The GroupBy functionality in JMP is amazingly useful!
There are some details where it can be optimized - existing posts from the wish list:

- "Group by" indicator in column list 

- Make adding and removing group by columns from quick formulas more intuitive 

- group by excluded()  /Formula Editor: meaningful results with excluded rows