set analysis time based

[Anonymous]

Hello -

I have a table with two columns

date	author
2/1/2011	john
2/1/2011	jerry
2/1/2011	jack
2/8/2011	john
2/8/2011	jack
2/8/2011	vijay

and I would like to use set analysis to identify the new author(s) in some timeframe pop out (if the timeframe is 1 week in this case, vijay will pop out).

I have tried an expression as follows but it isn't quite working:

concat(<date/={"<=$(=timestamp(now()-7))"}>} author,',')

Here my timeframe is in the last 7 days.

this effectively produces jack, john and vijay instead of vijay alone.

Any help is appreciated.

[Oleg_Troyansky · Accepted solution]

something like this:

New authors in the last 7 days:

concat( {<author={"=min(date)>today()-7"}>}    author, ',')

[Anonymous]

Works like a charm Oleg!  Appreciate it.

Oleg how do I break down this expression? 

1) look for dates from the beginning of time that fall into the last week

2) What part of this tells the set analysis to expose the new authors (this is why I was playing with symmetric difference, ...)

Thx