Help! How to design charts with date calculations

[#1]

Hey guys. Need a little help here.

I have 2 tables, with a field in each table as such:

1 table has a "date received" field

1 table has a "date sent" field

basically, I need a chart that filters by month (Jan through Dec), then shows how many letters were sent out in a timely fashion. when a letter is received (date received), it has to go out (date sent) within 60 days. if it's sent within that time frame, it's in a "timely fashion".

I have no clue how to do this. From what I can tell, first I have to do a "date received - date sent" calculation, then a calculation that says if that <= 60, then count that as "good". The chart then should show this, broken down by month, as a percentage (100%, 99%).

Should this be done in 2 steps? Maybe create a table with "date received - date sent", then do a count of that?

Help!!! 

[#2]

Try using below expression .

count(if((DateSent-DateReceived)<=60,DateSent))

[#3]

Awesome! Where would I use that expression, if I wanted to supply this data in a chart? (Sorry - I'm still quite a novice.)

[sujeetsingh]

Just go for a expression and add it in a chart or Table you want

[#5]

thanks everyone. you bunch of smarties.

[#6]

thanks everyone. you bunch of smarties.