Conditional expression with sub

[danimarc12]

Hello everyone!

I have an issue with an expression. I want to calculate the AVG of field1 - field2 with the condition that field1-field2 < 1.

this is my expression:

avg({<"$(=approvatoData-dataOrdineEora < 1)">}approvatoData-dataOrdineEora)

of course it doesn't work. Can anyone help me to write it correct and the reason of the correct method?

Thank you all!

[danimarc12]

PS. approvatoData and dataOrdineEora are two datetime fields