InfoPath Dev

I'm trying to add a rule to a repeating table so that when a date is selected from the date pick list the following will happen.

 If the date is already selected in the repeating table then the field "allowance" will be populated with 0

 Any thoughts/suggestions would be greatly appreciated! 

 thanks

here you go

on the calender control of you repeating write a rule to set the value of a field say

rule 1) field4 to eval(eval(group2, 'concat(my:field3, "|")'), "..")

where group2 is your repeating table and field3 is calendar control.

rule 2) if field4 contains field3

then field 5= substring-after(field4, .)

rule3) if field5 contains field3

then allowance= 0

field4 and filed 5 are not part of repeating table