Need help in set analysis

[#1]

This the scenario:
i've a table containg columns lets say...

DATE     Prev DATE      AMT

i want a chart displayin two bar graphs:

1)  AMT for current selection DATE

2) AMT for DATE=Current selection Prev DATE

how can we achive the second expression using set analysis method... ???

[Michiel_QV_Fan]

Please try this:

sum({$<Date = p({$<PrevDate>}Date)>}AMT)