Calculate difference in attend between these month and the previous

[abTech]

want to calculate the total attendance difference between a period of time lets take NOV & DEC 

i try with these expression but dosn't work 

Sum({<Date >= '12/1/2023' and Date <= '12/31/2023'> Attendance})

[rubenmarin]

Hi, that syntax has some errors, it could be:

Sum({<Date={">=12/1/2023<=12/31/2023"}>} Attendance)

For this to work the field Date has to store a real date type, with the format M/D/YYYY

[abTech]

Thank you for your review but it come with error in set modifier ad hoc element list while the date format is the same as date in the column.

[Ahidhar]

try this

sum({<Date={">=$(=monthstart(addmonths(max(Date),-1))) <=$(=max(Date))"}>}attendance)

[rubenmarin]

Hi, I've checked and I don't get any errors, check if your field names are Date and Attendance, with the same uppercase and lowercase.