Set Modifier not working field1=field2

[shanemichelon]

Hi everyone. I have a set modifier that is very simple but doesn't seem to work.  Here is my test load script:

load * inline [
Date, DateLY, Amount
1/1/2021,1/1/2020,10
1/1/2020,1/1/2019,9
];

And my Set expression: Sum({$<Date=DateLY>} Amount)

It is giving zero for all dates in a simple table with a dimension of Date and the measure.

I'm not sure what I am doing wrong.

[Saravanan_Desingh · Accepted solution]

Try this,

Sum({<Date=p(DateLY)>}Amount)

[shanemichelon]

Thanks.  That does seem to work.  I am curious as to why the documented option of just Field1=Field2 doesn't work?